Use substitution to solve the system of equations.5x + 5y = -302x - y = 15?
107281
Okay, I see your two equations are 5x + 5y = -30 and \n2x - y = 15.  I'm not certain if these are right so I'll explain how to solve systems of equations in general.\nThe way we solve a system of equations by substitution is to solve one of the equations for one of the variables.  We then take what that variable is equal to and substitute it into the equation we did not yet touch.  We then solve the resulting equation.  \nThe explanation is confusing so I will provide an example.\n4x + y = 9\n-x + 3y = 1\nSo I'll solve the second equation for x like so:\n-x + 3y = 1\n-x = 1 - 3y\nx = 3y -1\nThen, I substitute 3y - 1 into the first equation for x, since this expression is equal to x.\n4x + y = 9\n4(3y-1) + y = 9\n12y - 4 + y = 9\nAdding four to both sides and combining like terms I get:\n13y = 13\nTherefore y = 1.\nWe can then solve for x using one of the original equations, we'll pick 4x + y = 9.\n4x + y = 9, and we know y=1 so:\n4x + 1 = 9\nSubtracting 1 and solving gives us\n4x = 8, and therefore x = 2.\nYou can use this same process to solve your problem.  I suggest starting by solving the second equation for y.\nHope this helps, please remember to come back and choose a best answer!  :-)
86546
(3y+1)(-2)+y\n-6y-3+y\n-5y-3\n\n12s+(7-s)2\n12s+14-2s\n10s+14\n\n7x-3x(x+1)\n7x-3x^2-3x\n-3x^2+4x\n\n3t(t-5)+6t^2\n3t^2-15t+6t^2\n9t^2-15t\n\n4w^2-w(2w-3)\n4w^2-2w^2+3w\n2w^2+3w
141598
If we break down 25x^2, we get 5x.\n\nIf we break down 49y^2, we get 7y.\n\nThe resulting equation is:\n\n(5x + 7y)(5x - 7y)\n\nSolve it from there.
783856
First, you should know that you can multiply any one of these equations through by a nonzero constant, without changing the solution. You can also add or subtract any two of the equations term by term without changing the solution.\n\nWe begin by adding equations 1 and 3 together\nx+y+z = -5\nx-y+4z=12\n---------------\n2x + 5z = 7  (notice that the ys cancel out)\n\nNow we triple equation 1, and subtract equation 2 from it\n\n3x+3y+3z= -15\n2x+3y-2z = 8\n--------------------\nx +5z = -23\n\nNow we have two equations, in which we have eliminated y.\nWe subtract them, and solve for x.\n\n2x + 5z = 7 \nx    +5z = -23\n-----------------\nx = 7 - (-23) = 30\n\nIt is easy to find y and z, now that we know x is 30/\n\nx + 5z = -23\n30 + 5z = -23\n5z = -53\nz = -(53/5) or -10.6\n\nx + y + z = -5\n30 + y + (-53/5) = -5\ny = 53/5 - 30 - 5 = -24.4\n\nSo (x,y,z) = (30,-24.4,-10.6)
714041
10x+4y+4\n\nor can be written as y= -2.5x-1
222015
5x - 2y = 4  (1)\n2x + 3y = 13 (2)\nmul. eq.(1) by 2: 2 (5x - 2y = 4)\n                    10x - 4y = 8\n\nmul. eq.(2) by 5: 5 (2x +  3y = 13)\n                    10x + 15y = 65\n\nsubtract: 10x -  4y =  8\n      (-) 10x + 15y =  65\n          ________________\n               -19y =  -57 \n                  y =  -57/-19\n                  y =  3\n\nsubstitute value of y to any of the eqs.\n\nSubstituting to eq. (1):\n\n    5x - 2y   = 4   \n    5x - 2(3) = 4\n    5x - 6    = 4\n    5x              = 4 + 6\n    5x              = 10\n     x              = 10/5\n     x              = 2\n\nso, x = 2\n    y = 3\n\nto check, substitute values of x and y to any of the two equations:\n    for eq. (1),\n\n    5x   - 2y   = 4   \n    5(2) - 2(3) = 4\n      10 - 6    = 4\n\n    for eq. (2),\n\n    2x   + 3y   = 13\n    2(2) + 3(3) = 13\n      4  + 9    = 13
783854
why not, you just plug y in the 1st equation:\n5x + 3y = -19   & y=-2x-8\n5x + 3(- 2x - 8) = -19\nand solve for x\n5x - 6 x - 24 = -19\n-x - 24 = -19\n-x = 24 - 19 = 5\nx = -5\ny = -2x-8\ny = -2(-5) - 8\ny = 10 - 8 = 2\n\nx = -5 , y = 2
930265
4x + 3y=27\n4x-2y   = 2\nnow subtract the second equation from the first.\n5 y = 25\ny = 25/5  = 5 \n2x-5 = 1\n2x = 6\nx = 3\nTest any of the two equation substituting values for x and y.
516161
x-y+3x-5y+3=0\n\n4x - 6y + 3 = 0\n\n4x + 3 = 6y\n\n2x/3 + 1/2 = y
709836
2x -  4y = -5\n3x + 4y = -15\n\n5x = -20\n\nx = -20/5                                       \n\nx = -4\n\n*************************\n\n2(-4) - 4y = -5\n\n-8 - 4y = -5\n\n- 4y = -5 + 8\n\n- 4y = 3              \n\ny = -3/4\n\n**************************\n2 (-4) - 4 (-3/4) = -5                                        \n\n-8 - (-3) = -5           \n\n&\n\n3 (-4) + 4 (-3/4) = -15                           \n\n-12 + (-3) = -15
887085
First, I multiplied the first equation by 2 and the second one by -5 in order to make it easy for me to cancel out both x's.\n2(-5x+7y=-40)\n-5(-2x+4y=-16)\n\n-10x+14y=-80\n10x+-20y=80\n\nNow, you can actually cancel out the x's and the constants at the end.\n\n-6y=0\ny=0\n\nNow you plug y=0 into one of the equations to find x.\n\n-5x + 7(0) = -40\n-5x +0 = -40\n-5x = -40\nx = 8\n\n(0,8) is the answer.
959788
You got y right.  Now plug 30 in for y in one of your oringal equations to solve for x.\n\n2x + 5y = 20\n2x +5(3) = 20\n2x + 15 = 20\n2x = 5\nx = 5/2\n\nNow plug in x=5/2 and y=3 in your other equation to check your work.\n\n-2(5/2) + 5(3) = \n-5 + 15 = 10\n\nIt checks out, so both your x and y are correct.\n\nTIP:  I think you got x=0 from your 0+10y=30 equation.  If so, please know you can't use that for x, just for y.  You got rid of the x's by adding the equations so that you could isolate y and solve for y only.  Once you have y, you have to go back to one of your equations that has x in it in order to solve for x.
114816
-3+5=5-3y+4y       \n   2=5+y\n  2-5=y \n   -3=y\n because...          2=5-3(-3)+4(-3)\n                     2=5+9-12 \n                     2= 14-12         \n                     2=2
525451
5y -3y = 14 -3\n2y = 11\ny = 5.5\n\n5y -3y = 14 - 9\n2y = 5\ny = 2.5
260573
Well, we know that y = 7, so just plug that into the first equation and solve for x.\n\nx + 7 = 5\nx = 5 - 7\nx = -2\n\nANSWER : (-2, 7)
918448
-3x+15y=-30\n\nWe'll divide everything by 3 to make it easier\n\n-x+5y=-10\n\nWe have x - 5y = 10\n\nIf we multiply that equation by -1, we get\n-x+5y=-10!\n\nThis is the same as the simplified -3x+15y=-30, which means that any x and its corresponding y value fits both equations.\n\nIf they are the same equation, then all values of x (and the necessary values of y) will work; the solution is all numbers x.\n\nHope this helps.
958973
y=5x+2\ny=5(2)+2\ny=10+2\ny=12