100=1.75(x*x)-4x

Solution for 100=1.75(x*x)-4x equation:

100=1.75(x*x)-4x

We move all terms to the left:

100-(1.75(x*x)-4x)=0

We add all the numbers together, and all the variables

-(1.75(+x*x)-4x)+100=0


We calculate terms in parentheses: -(1.75(+x*x)-4x), so:

1.75(+x*x)-4x

We add all the numbers together, and all the variables

-4x+1.75(+x*x)

We multiply parentheses

1.75x^2-4x

Back to the equation:

-(1.75x^2-4x)


We get rid of parentheses

-1.75x^2+4x+100=0

a = -1.75; b = 4; c = +100;
Δ = b2-4ac
Δ = 42-4·(-1.75)·100
Δ = 716
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{716}=\sqrt{4*179}=\sqrt{4}*\sqrt{179}=2\sqrt{179}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-2\sqrt{179}}{2*-1.75}=\frac{-4-2\sqrt{179}}{-3.5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+2\sqrt{179}}{2*-1.75}=\frac{-4+2\sqrt{179}}{-3.5}
$