Question

What are the solutions for the quadratic equation 2x^2+x=3

1) -1 , 3/2
2) 1 , 3/2
3) 1 , -3/2
4) -1 , -3/2

Answer 1

x = -3/2, 1. It is Choice 3.

Explanation:

2x^2 + x - 3 = 0

Use the 'ac' method:-

2* -3 = -6 so we need 2 numbers whose produce is -6 and whose sum is +1 .

They are = +3 and - 2. So we write

2x^2 - 2x + 3x - 3 = 0

Factor by grouping:-

2x(x - 1) + 3(x - 1) = 0

(2x + 3)(x - 1) = 0

giving x = -3/2 , 1.