5(x)=-4.9x^2+20x+1

Solution for 5(x)=-4.9x^2+20x+1 equation:

5(x)=-4.9x^2+20x+1

We move all terms to the left:

5(x)-(-4.9x^2+20x+1)=0

We get rid of parentheses

4.9x^2-20x+5x-1=0

We add all the numbers together, and all the variables

4.9x^2-15x-1=0

a = 4.9; b = -15; c = -1;
Δ = b2-4ac
Δ = -152-4·4.9·(-1)
Δ = 244.6
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-\sqrt{244.6}}{2*4.9}=\frac{15-\sqrt{244.6}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+\sqrt{244.6}}{2*4.9}=\frac{15+\sqrt{244.6}}{9.8}
$