Question

If x² – 3x + 2 = 0, values of x correct to one decimal place are ______.

Options

• 2.0 and 1.0

• 2.0 or 1.0

• 3.0 and 2.0

• 3.0 or 2.0

Answer 1

If x² – 3x + 2 = 0, values of x correct to one decimal place are 2.0 or 1.0.

Explanation:

Given quadratic equation be

x² – 3x + 2 = 0

On comparing with ax² + bx + c = 0

We have a = 1; b = – 3 and c = 2

By quadratic formula,

`x = (-b ± sqrt(b^2 - 4ac))/(2a)`

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

= `(3 ± sqrt(9 - 8))/2`

= `(3 ± 1)/2`

= `(3 + 1)/2` or `(3 - 1)/2`

= 2 or 1

∴ x = 2.0 or 1.0