60=(x+10)(x+3)

Solution for 60=(x+10)(x+3) equation:

60=(x+10)(x+3)

We move all terms to the left:

60-((x+10)(x+3))=0

We multiply parentheses ..

-((+x^2+3x+10x+30))+60=0


We calculate terms in parentheses: -((+x^2+3x+10x+30)), so:

(+x^2+3x+10x+30)

We get rid of parentheses

x^2+3x+10x+30

We add all the numbers together, and all the variables

x^2+13x+30

Back to the equation:

-(x^2+13x+30)


We get rid of parentheses

-x^2-13x-30+60=0

We add all the numbers together, and all the variables

-1x^2-13x+30=0

a = -1; b = -13; c = +30;
Δ = b2-4ac
Δ = -132-4·(-1)·30
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-17}{2*-1}=\frac{-4}{-2}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+17}{2*-1}=\frac{30}{-2}
=-15
$