Question

Use the quadratic formula to solve x^2 + 9x + 10 = 0. Estimate irrational solutions to the nearest tenth.

A {–3.6, 16.4}
B {–7.7, –1.3}
C {–25, 16}
D {–15.4, –2.6}

Answer 1

`x^(2) + 9x + 10 = 0 \\x = \frac{-(9) +/- \sqrt{(9)^(2) - 4(1)(10)}}{2(1)} \\x = (-9 +/- √(81 - 40))/(2) \\x = (-9 +/- √(41))/(2) \\x = (-9 +/- 6.4)/(2) \\x = (-9 + 6.4)/(2) \\x = (-2.6)/(2) \\x = -1.3 \\ \\x = (-9 - 6.4)/(2) \\x = (-15.4)/(2) \\x = -7.7`

It is equal to B.

Answer 2

Basically, just plus your numbers into quadratic formula. A= 1, B= 9, C= 10.
The answer you will get is B.