Question

Solve by factorization
2x^2 + 3x -20 = 0

Answer 1

x = 5/2, -4.

Explanation:

2x^2 + 3x - 20

NOTE: 2 * -20 = -40 so we need 2 numbers whose product is - 40 and whose sum is + 3. These are + 8 and -5, so we write

= 2x^2 + 8x - 5x - 20 Factor by grouping:

= 2x(x + 4) - 5(x + 4)

= (2x - 5)(x + 4)

so x = 5/2, -4 are the roots.

Answer 2

x=2.5 or x=-4

Explanation:

factorisation= factors:1, 2, 4, 5, 10, 20 (only the positive factors)

We will use the factors 4 and 5.

=(2x-5)(x+4)=0

2x-5=0 || x+4=0

2x=+5 || x=-4

x=2.5 or x=-4