Question

2x2+7x-15=0 find the roots

Answer 1

Answer:

x = - 5, x = $\frac{3}{2}$

Step-by-step explanation:

Consider the product of the factors of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term.

product = 2 × - 15 = - 30, sum = + 7

The factors are + 10 and - 3

Use these factors to split the middle term

2x² + 10x - 3x - 15 = 0 ( factor first/second and third/fourth terms )

2x(x + 5) - 3(x + 5) = 0 ← factor out (x + 5)

(x + 5)(2x - 3) = 0

equate each factor to zero and solve for x

x + 5 = 0 ⇒ x = - 5

2x - 3 = 0 ⇒ 2x = 3 ⇒ x = $\frac{3}{2}$

Answer 2

Answer:

hello :

2x² +7x - 15 = 0...   a = 2   b = 7   c = - 15

Δ = b² - 4ac = 7² - 4(2)(- 15) = 49 + 120 = 169 = 13²

x1 = (-7 +13)/2  = 3

x2  = (-7 - 13)/2 = - 10

the roots are : 3  , - 10