Question

What are the solutions to the equation 3x2 + 15x = 18?

A X=-3 and X =-2
B X = -6
and x = 1
C
X = 6 and x = 13
D X = 0 and x = 1

Answer 1

`3x {}^(2) + 15x = 18`

Divide the entire thing by 3

`x {}^(2) + 5x = 6`

`x {}^(2) + 5x - 6 = 0`

You can find the roots by using the quadratic formula or by using the form x²-Sx+P

`let \: \alpha \: and \: \beta \: be \: the \: roots`

Two numbers whose sum is -5 and product is -6

-6 and +1

Your answer is B