Question

Please help i need this ASAP

Answer 1

-5

Explanation:

First, find the solutions to the quadratic equation.

`3x^2+15x+9=0\\3(x^2+5x+3)=0`

Since this is not factorable, use the quadratic formula and simplify.

x = (-5±
`√((5)^2-4(1)(3))`)÷2(1)

x = (-5±
`√(13)`)÷2

So x1 = (-5+
`√(13)`)÷2 and x2 = (-5-
`√(13)`)÷2

Now just sub it into the equation and simplify:

(-5+
`√(13)`)÷2 + (-5-
`√(13)`)÷2

=
`(-5+√(13) + (-5)-√(13))/(2)`

=
`((-5)+(-5)+√(13)-√(13) )/(2)`

=
`(-10)/(2)`

= -5