0=10x(7+10x)

Solution for 0=10x(7+10x) equation:

0=10x(7+10x)

We move all terms to the left:

0-(10x(7+10x))=0

We add all the numbers together, and all the variables

-(10x(10x+7))+0=0

We add all the numbers together, and all the variables

-(10x(10x+7))=0


We calculate terms in parentheses: -(10x(10x+7)), so:

10x(10x+7)

We multiply parentheses

100x^2+70x

Back to the equation:

-(100x^2+70x)


We get rid of parentheses

-100x^2-70x=0

a = -100; b = -70; c = 0;
Δ = b2-4ac
Δ = -702-4·(-100)·0
Δ = 4900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4900}=70$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-70}{2*-100}=\frac{0}{-200}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+70}{2*-100}=\frac{140}{-200}
=-7/10
$