how do you solve: 2x^4 - 7x^2 - 4 = 0     thank you?
156051
first let T =X^2\nthan we get a second degree equation\n2T^2-7T-4=0\nso you can solv it easyer
986257
If the equation is X^4 - 12x^2 -64 =0, there is.\n\nUse u = x^2, now your equation will look like this:\n\nu^2 - 12u - 64 =0\nFind u1 and u2 using the quadratic formula.\n\nThe solutions are u1 = 16, u2 = -4\n\nNow you go back to x, first deal with u1, then u2.  Because u = x^2 each u solution will give you two x solutions.\n\n\nu = x^2 = 16\nx = +/- SQRT(16)\nx1 = 4\nx2 = -4\n\nx2 = -4.  This is not possible with real numbers. so it will give you two imaginary numbers. Do the same as before\n\nx = +/- SQRT(-4) = +/- 2*SQRT(-1) = +/- 2i\n\nx3 = i\nx4 = -i
911592
Factorize!\n4x (x^2-9) = 0\n4x (x+3) (x-3)\n\nyour solution is \nX = 0\nx= -3\nx= 3
825795
OK,as the first one is already done,I am doing the rest for you\n4(2x-6)=x+2 =>8x-24=x+2  =>8x-x=2+24  =>7x=26  =>x=26/3=8 2/3  (3) 2(x+5)+1=3(x-1)+4   =>2x+10+1=3x-3+4 =>2x-3x=-3+4-10-1  => -x=-4  =>x=1  (5)x+6=4(4x-1)   =>x+6=16x-4  =>x-16x=-4-6  => -15x=-10  =>x=-10/-15=2/3 [after reducing]
978909
4^x-2^x-12=0\n(2^x)^2-2^x-12=0\nset 2^x=y\ny^2-y-12=0\n(y-4)(y+3)=0\ny=4 or -3\n2^x=2^2\nx=2\nignore the x=-3
301645
If you have an equation like 5x^2 + 7x - 6 = 0:\n\nGet the x^2 term by itself\nx^2 + 7x/5 - 6/5 = 0\n\nMove the constant to the other side\nx^2 + 7x/5 = 6/5\n\nTake half of the coefficient for the x term and square it: half of 7/5 is 7/10, squared is 49/100. Add this to both sides of the equation\n\nx^2 + 7x/5 + 49/100 = 6/5 + 49/100\nx^2 + 7x/5 + 49/100 = 169/100\n\nThe left side is a perfect square trinomial - factor it\n(x + 7/10)^2 = 169/100\n\nTake the square root of both sides and solve for x\nx + 7/10 = +/- 13/10\nx = -7/10 +/- 13/10\nx = 6/10 or -20/10\nx = 0.6 or -2
749124
x^2 + 4x + 4=7  (first put it in the form ax^2 + bx + c = 0, by subtracting 7 from both sides of the equation)\n\nx^2 + 4x - 3 = 0   (this is called a quadratic equation)\n\nNow substitute a =1, b = 4, c = -3 in the following formula\n\nx equals -b plus or minus the square root of (b^2 - 4ac) all over 2a\n\nBecause you are solving for x^2 you expect to get 2 answers.  The plus or minus in the middle of the formula gets you 2 answers as you solve the formula for both plus and minus the square root of (b^2 minus 4ac).\n\n[If you're going to have to do this in an exam, it's probably worth learning the formula off by heart.  It's boring to have to do so but you'll probably have more confidence in the exam if you see an quadratic equation and already know the formula.]\n\nGood luck for the working out - you can do this bit!
618060
this would multiply out to be 4x^2-9\n\nif you let the expression be equal to 0, then x would be positive or negative 3/2 because either (2x+3) = 0 or (2x-3) = 0, and just solve for x
834770
3x^2-x-4=0\n=> 3x^2-4x+3x-4=0\n=> x(3x-4)+1(3x-4)=0\n=>(3x-4)(x+1)=0\nTherefore,either 3x-4=0 or x+1=0\nIf 3x-4=0,then x=4/3,and \nif x+1=0,then x=-1\nTherefore, x=4/3 or -1 ans
819492
3^4 = -2x^2 + 8\n81 = -2x^2 + 8   simplify\n73 = -2x^2          subtract 8 from both sides\n-73/2 = x^2         divide both sides by -2\nsqrt(73/2) * i = x   take square root of both sides... since the right is negative you get an imaginary number.  i = sqrt(-1)
1133153
7 - 2[4-6+2x] - 8+ x=6\n\n7 - 2[-2+2x] - 8 +x =6\n7 + 4 - 4x - 8 + x =6\n3 - 3x = 6\nx = -1\n\nDon't listen to the math goober - plug the value in and check it.
1054159
First, get rid of the brackets (multiply the terms inside the brackets by -1):\n\n7-2x^2 +2x -2 -2x -5 +2x^2\n\nCollect like terms:\n\n2x^2 -2x^2 +2x -2x +7-2-5 = 0\n\nIt's easy to see the sum is zero.
932643
4x + 7 = -7\n4x = 14\nx = 14/4\nx = 7/2
738884
x^2-5x-14=0\n=>x^2-7x+2x-14=0\n=>x(x-7)+2(x-7)=0\n=>(x-7)(x+2)=0\nTherefore either x-7=0 or x+2=0\nIf x-7=0,then x=7,and if x+2=0,then x=_2\nThereforex=7 or -2 ans
17048
= x^2 - 7x + 4x -28\n= x^2 - 3x - 28
912242
2-10x=3x^2+3x-7x-7\n2-10x=3x^2-4x-7\n0=3x^2+6x-9\n0=3(x^2+2x-3)\n0=(x+3)(x-1)\nx=-3 and 1
894689
-4x=28\ndivide both sides of the equation by -4 to get:\nx=-7