159=-5x+7x(7x-15)

Solution for 159=-5x+7x(7x-15) equation:

159=-5x+7x(7x-15)

We move all terms to the left:

159-(-5x+7x(7x-15))=0


We calculate terms in parentheses: -(-5x+7x(7x-15)), so:

-5x+7x(7x-15)

We multiply parentheses

49x^2-5x-105x

We add all the numbers together, and all the variables

49x^2-110x

Back to the equation:

-(49x^2-110x)


We get rid of parentheses

-49x^2+110x+159=0

a = -49; b = 110; c = +159;
Δ = b2-4ac
Δ = 1102-4·(-49)·159
Δ = 43264
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{43264}=208$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(110)-208}{2*-49}=\frac{-318}{-98}
=3+12/49
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(110)+208}{2*-49}=\frac{98}{-98}
=-1
$