-5a(a-7)-2a=35-7a

Solution for -5a(a-7)-2a=35-7a equation:

-5a(a-7)-2a=35-7a

We move all terms to the left:

-5a(a-7)-2a-(35-7a)=0

We add all the numbers together, and all the variables

-5a(a-7)-2a-(-7a+35)=0

We add all the numbers together, and all the variables

-2a-5a(a-7)-(-7a+35)=0

We multiply parentheses

-5a^2-2a+35a-(-7a+35)=0

We get rid of parentheses

-5a^2-2a+35a+7a-35=0

We add all the numbers together, and all the variables

-5a^2+40a-35=0

a = -5; b = 40; c = -35;
Δ = b2-4ac
Δ = 402-4·(-5)·(-35)
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-30}{2*-5}=\frac{-70}{-10}
=+7
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+30}{2*-5}=\frac{-10}{-10}
=1
$