(3+x)(2x+1)=

Solution for (3+x)(2x+1)= equation:

(3+x)(2x+1)=

We move all terms to the left:

(3+x)(2x+1)-()=0

We add all the numbers together, and all the variables

(x+3)(2x+1)-()=0

We add all the numbers together, and all the variables

(x+3)(2x+1)=0

We multiply parentheses ..

(+2x^2+x+6x+3)=0

We get rid of parentheses

2x^2+x+6x+3=0

We add all the numbers together, and all the variables

2x^2+7x+3=0

a = 2; b = 7; c = +3;
Δ = b2-4ac
Δ = 72-4·2·3
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{-(7)-5}{2*2}=\frac{-12}{4}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+5}{2*2}=\frac{-2}{4}
=-1/2
$