The roots of the quadratic equation x2 + 8x + 7 = 0 are A) 1, 7 B) -

1.	The roots of the quadratic equation x2 + 8x + 7 = 0 are A) 1, 7 B) -1, -7 C) -1, 7 D) 1, -7
Answer» Correct option is (B) -1, -7 Given quadratic equation is \(x^2+8x+7=0\) \(\Rightarrow x^2+7x+x+7=0\) \(\Rightarrow\) x (x+7) + 1 (x+7) = 0 \(\Rightarrow\) (x+7) (x+1) = 0 \(\Rightarrow\) x+7 = 0 or x+1 = 0 \(\Rightarrow\) x = -7 or x = -1 Hence, roots of given quadratic equation are x = -1 & x = -7. Correct option is B) -1, -7

The roots of the quadratic equation x2 + 8x + 7 = 0 are A) 1, 7 B) -1, -7 C) -1, 7 D) 1, -7

Answer»

Correct option is (B) -1, -7

Given quadratic equation is

\(x^2+8x+7=0\)

\(\Rightarrow x^2+7x+x+7=0\)

\(\Rightarrow\) x (x+7) + 1 (x+7) = 0

\(\Rightarrow\) (x+7) (x+1) = 0

\(\Rightarrow\) x+7 = 0 or x+1 = 0

\(\Rightarrow\) x = -7 or x = -1

Hence, roots of given quadratic equation are x = -1 & x = -7.

Correct option is B) -1, -7