(1/2x+15)+x=90

Solution for (1/2x+15)+x=90 equation:

(1/2x+15)+x=90

We move all terms to the left:

(1/2x+15)+x-(90)=0


Domain of the equation: 2x+15)!=0

x∈R


We add all the numbers together, and all the variables

x+(1/2x+15)-90=0

We get rid of parentheses

x+1/2x+15-90=0

We multiply all the terms by the denominator


x*2x+15*2x-90*2x+1=0

Wy multiply elements

2x^2+30x-180x+1=0

We add all the numbers together, and all the variables

2x^2-150x+1=0

a = 2; b = -150; c = +1;
Δ = b2-4ac
Δ = -1502-4·2·1
Δ = 22492
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:

$\sqrt{\Delta}=\sqrt{22492}=\sqrt{4*5623}=\sqrt{4}*\sqrt{5623}=2\sqrt{5623}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-150)-2\sqrt{5623}}{2*2}=\frac{150-2\sqrt{5623}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-150)+2\sqrt{5623}}{2*2}=\frac{150+2\sqrt{5623}}{4}
$