Question

One of the roots of the quadratic equation x² + 2x -15 =0 is -5, find the other root
A.15
B.5
C.3
D.-3

Pls show me the solution

Answer 1

Answer:

C.3

Step-by-step explanation:

let, x=3

3×3+2×3-15=0

9+6-15=0

15-15=0

0=0

3 is the root of given quadratic equation.

Answer 2

Answer:

Given,

a quadratic equation x^2 +2x -15=0

root of this equation = -5

to find : other root

Explanation:

let the other root be p

sum of roots = -b/a

-5+p = -2/1

-5+p = -2

-5+2 = -p

-3 = -p

p= 3

the other root = 3