4/5x-1/4x=87

Solution for 4/5x-1/4x=87 equation:

4/5x-1/4x=87

We move all terms to the left:

4/5x-1/4x-(87)=0


Domain of the equation: 5x!=0

x!=0/5

x!=0

x∈R



Domain of the equation: 4x!=0

x!=0/4

x!=0

x∈R


We calculate fractions


16x/20x^2+(-5x)/20x^2-87=0

We multiply all the terms by the denominator


16x+(-5x)-87*20x^2=0

Wy multiply elements

-1740x^2+16x+(-5x)=0

We get rid of parentheses

-1740x^2+16x-5x=0

We add all the numbers together, and all the variables

-1740x^2+11x=0

a = -1740; b = 11; c = 0;
Δ = b2-4ac
Δ = 112-4·(-1740)·0
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-11}{2*-1740}=\frac{-22}{-3480}
=11/1740
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+11}{2*-1740}=\frac{0}{-3480}
=0
$