How do you solve 2x^2-5x=-7 using the quadratic formula?

1 Answer
May 31, 2017

x can either equal 3.5 or -1

Explanation:

2x^2 - 5x = -7

To make the answer 0, which we need in a quadratic equation, we can just move the -7 to the opposite side.

2x^2 - 5x + 7= 0

Now we can use the Quadratic formula to solve the question.

ax^2 + bx + c = 0

x = (-b+- sqrt(b^2 - 4ac))/(2a)

a = 2
b = -5
c = 7

x = (5+- sqrt(-5^2 - 4 xx 2 xx 7))/(2 xx 2)

x = (5+- sqrt(-25 - 8 xx 7))/4

x = (5+- sqrt(-81))/4

x = (5+- 9)/4

x_1 = (5 + 9)/4

x_1 = 14/4

color(blue)(x_1 = 3.5

x_2 = (5 - 9)/4

x_2 = (-4)/4

color(blue)(x_2 = -1