A=(7x+3)(7x+3)

Solution for A=(7x+3)(7x+3) equation:

=(7A+3)(7A+3)

We move all terms to the left:

-((7A+3)(7A+3))=0

We multiply parentheses ..

-((+49A^2+21A+21A+9))=0


We calculate terms in parentheses: -((+49A^2+21A+21A+9)), so:

(+49A^2+21A+21A+9)

We get rid of parentheses

49A^2+21A+21A+9

We add all the numbers together, and all the variables

49A^2+42A+9

Back to the equation:

-(49A^2+42A+9)


We get rid of parentheses

-49A^2-42A-9=0

a = -49; b = -42; c = -9;
Δ = b2-4ac
Δ = -422-4·(-49)·(-9)
Δ = 0
Delta is equal to zero, so there is only one solution to the equation

                              Stosujemy wzór:
$A=\frac{-b}{2a}=\frac{42}{-98}=-3/7$