Question

Choose the correct answer from the given four options :

The roots of the equation x² – 3x – 10 = 0 are

Options

• 2,- 5

• – 2, 5

• 2, 5

• – 2, – 5

Answer 1

x² – 3x – 10 = 0

x = `(-(-3) ± sqrt((-3)^2 - 4 xx 1 xx (-10)))/(2 xx 1)`

= `(3 ± sqrt(9 + 40))/(2)`

= `(3 ± sqrt(49))/(2)`

= `(3 + 7)/(2)`

∴ x = `(3 + 7)/(2)` = 5
and
x = `(3 - 7)/(2) = (-4)/(2)` = –2
x = 5, – 2 or – 2, 5.