How do you solve $2 x^{2} - 15 x = 8$ $2x^2 - 15x = 8$ ?

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Answer 1 · 2017-01-31T14:42:14

The solutions are $S = {- \frac{1}{2}, 8}$ $S={-1/2, 8}$

Let's rewrite the equation

$2 x^{2} - 15 x - 8 = 0$ $2x^2-15x-8=0$

And compare this to the quadratic equation

$a x^{2} + b x + c = 0$ $ax^2+bx+c=0$

We start by calculating the discriminant

$Delta=b^2-4ac=(-15)^2-4(2)(-8)=225+64=289$

The solutions are

$x=(-b+-sqrtDelta)/(2a)$

$x_1=(15+sqrt289)/(2*2)=(15+17)/4=8$

$x_2=(15-17)/(2*2)=-2/4=-1/2$

How do you solve 2x^2 - 15x = 82x2−15x=82x^2 - 15x = 8?