(2x+6)(4x+7)=

Solution for (2x+6)(4x+7)= equation:

(2x+6)(4x+7)=

We move all terms to the left:

(2x+6)(4x+7)-()=0

We add all the numbers together, and all the variables

(2x+6)(4x+7)=0

We multiply parentheses ..

(+8x^2+14x+24x+42)=0

We get rid of parentheses

8x^2+14x+24x+42=0

We add all the numbers together, and all the variables

8x^2+38x+42=0

a = 8; b = 38; c = +42;
Δ = b2-4ac
Δ = 382-4·8·42
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(38)-10}{2*8}=\frac{-48}{16}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(38)+10}{2*8}=\frac{-28}{16}
=-1+3/4
$