Question

Which of the following have both 2 and -5 as solutions.

a. x2 + 3× - 10 = 0
b. x2- 3x -10=0
c. x2 + 7× +10=0
d. x2 -7x +10=0

Answer 1

`x_1=2\ \ \ and\ \ \ x_2=-5\\\\ \Rightarrow\ \ \ (x-x_1)(x-x_2)=(x-2)(x+5)=x^2+5x-2x-10=\\\\.\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ =x^2+3x-10\ \ \ \Rightarrow\ \ \ Ans.\ a.`

Answer 2

`x_1=2;\ x_2=-5\\\\(x-2)(x-(-5))=(x-2)(x+5)=x^2+5x-2x-10=x^2+3x-10\\\\Answer:a.`