Find X and Y, by adding: 2x + 5y =20  and  -2x +5y =10?
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.
796832
5(2^2)+5(2)+2y=2\n2y=-28\ny=-14\n10x+5+y+x(dy/dx)=0\nx(dy/dx)=-10x-5-y\ndy/dx=(-10x-5-y)/x\n(-10*2-5-(-14))/2\n-11/2\ni hope thats right
631059
3y+5=y-25\n2y+5=-25\n2y=-30\ny=-15\n\nSee, you just use inverse operations.\n\n4n-5=2n+3\n2n-5=3\n2n=8\nn=4\n\nSo your answers are y=-15 and n=4. I hope that helped!
846702
-x + 2y = 18\n x + 8y = -38\n\nadd up these two lines\n\n0x+ 10y = -20\ny= -20/10 = -2\n\nx + 8(-2) = -38\nx - 16 = -38\n\n\nx=-22\ny=-2
479219
2x + 5y = 8\n5x - 2y = 20\n\nSince none of the coefficients are multiples of one another, you must choose either and find a common factor.  One easy way to do it is to multiply the top equation by 5 and the bottom by -2\n\nThen they become\n\n10x + 25y = 40\n-10x + 4y = -40\n\nAdd the two equations and you get\n29y = 0 this gives y = 0 as one solution\n\nIf y = 0 then substitute the value into either equation:\n\nFor example, 2x + 5(0) = 8\n\nThen x = 4\n\nThe final solution is (4, 0) You can check the answer by substituting the answer into both equations to see if it makes them both true.
1021939
2x+y=3..........eq 1         -2x+5y=-9..............eq 2\nAdd eq. 1 and 2\n6y=-6\ny=-1\nPutting this value in eq 1\nx=2\nS.S={ 2, -1}\n\n3x+5y=0............eq 3           2x-5y=-25.................4\nMultiply eq 3 by 2 and eq 4 by 3\nFrom eq 3: 6x+10y=0................eq 5\nFrom eq 4: 6x-15y=-75..............eq 6\nSubtract eq 6 from 5\ny=3\nPut the value of y in eq 3\nx=-5\nS.S={ -5, 3}
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
395515
6x+2y=10\nsubract 6x fro both sides\n2y=-2x+10\ndivide both sides by 2\ny=-x+5
714041
10x+4y+4\n\nor can be written as y= -2.5x-1
679397
y = 0.5x-4 \n\nor similarly\n\nx= 2y +8
807209
I can tell you just by looking at this that it won't work, but here's the process:\nMultiply the first equation by 2 so the x coefficient in the first equation is the opposite (negative) of the x coefficient in the second equation:\n2x + 10y = 20\nMove the y and the constant in the second equation to make it match the formet of the first\n-2x -10y = -20\nAdd the two equations to get:\n2x + 10y = 20\n+(-2x -10y = -20)\n----------------------\n0 = 0\n\nThere is no single solution, because the two equations are actually the same equation written differently.
870236
Let's use elimination.\nMultiply the first equation by 4 and multiply the second equation by 3, and then add them.\n8x - 12y = -4\n9x + 12y = 24\n17x = 20\nx = 20/17\nTo find y, just replace x with 20/17 in one of the equations and solve for y.\n2(20/17) - 3y = -1\n40/17 - 3y = -1\n-3y = -1 - 40/17\n-3y = -17/17 - 40/17\n-3y = -57/17\nMultiply both sides by -1/3\ny = (-57/17)(-1/3)\ny = 19/17\nAnswer: x = 20/17 and y = 19/17 \nor you could write it as (20/17, 19/17)
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
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.
264673
Let x = # of 20's\ny = # of 50's\n\nx + y = 32\n20x + 50y = 1000 or\n2x + 5y = 100\n\nfrom the first equation, we know that x = 32 - y. Simply substitute this to the remaining equation and solve for the value of y.\n\n2(32 - y) + 5y = 100\n64 - 2y + 5y = 100\n3y = 36\ny = 12\n\nThe answer is 12 ^_^
232592
2x = 3y - 4y + 5 - 2\n2x = -y + 3\n2x + y = 3
2156
5x+9y=18\nsubtract 5x from both sides because you want Y by itself\n\n9y=18-5x\ndivide both sides by 9 because you want Y by itself\n\ny=2-5/9x<---------------There you have it, simplified