3x+1+15=(12.5)x2

Solution for 3x+1+15=(12.5)x2 equation:

3x+1+15=(12.5)x2

We move all terms to the left:

3x+1+15-((12.5)x2)=0

We add all the numbers together, and all the variables

3x-((12.5)x2)+16=0


We calculate terms in parentheses: -((12.5)x2), so:

(12.5)x2

We multiply parentheses

12.5x^2

Back to the equation:

-(12.5x^2)


We get rid of parentheses

-12.5x^2+3x+16=0

a = -12.5; b = 3; c = +16;
Δ = b2-4ac
Δ = 32-4·(-12.5)·16
Δ = 809
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{-(3)-\sqrt{809}}{2*-12.5}=\frac{-3-\sqrt{809}}{-25}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{809}}{2*-12.5}=\frac{-3+\sqrt{809}}{-25}
$