(3x+8)(x=-1)

Solution for (3x+8)(x=-1) equation:

(3x+8)(x=-1)

We move all terms to the left:

(3x+8)(x-(-1))=0


We calculate terms in parentheses: +(3x+8)(x-(-1)), so:

3x+8)(x-(-1)

We add all the numbers together, and all the variables

3x+8)(x+1

Back to the equation:

+(3x+8)(x+1)


We multiply parentheses ..

(+3x^2+3x+8x+8)=0

We get rid of parentheses

3x^2+3x+8x+8=0

We add all the numbers together, and all the variables

3x^2+11x+8=0

a = 3; b = 11; c = +8;
Δ = b2-4ac
Δ = 112-4·3·8
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-5}{2*3}=\frac{-16}{6}
=-2+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+5}{2*3}=\frac{-6}{6}
=-1
$