-7/8x-9/40+1/5x=-72

Solution for -7/8x-9/40+1/5x=-72 equation:

-7/8x-9/40+1/5x=-72

We move all terms to the left:

-7/8x-9/40+1/5x-(-72)=0


Domain of the equation: 8x!=0

x!=0/8

x!=0

x∈R



Domain of the equation: 5x!=0

x!=0/5

x!=0

x∈R


We add all the numbers together, and all the variables

-7/8x+1/5x+72-9/40=0

We calculate fractions


(-1800x^2)/6400x^2+(-5600x)/6400x^2+1280x/6400x^2+72=0

We multiply all the terms by the denominator


(-1800x^2)+(-5600x)+1280x+72*6400x^2=0

We add all the numbers together, and all the variables

(-1800x^2)+1280x+(-5600x)+72*6400x^2=0

Wy multiply elements

(-1800x^2)+460800x^2+1280x+(-5600x)=0

We get rid of parentheses

-1800x^2+460800x^2+1280x-5600x=0

We add all the numbers together, and all the variables

459000x^2-4320x=0

a = 459000; b = -4320; c = 0;
Δ = b2-4ac
Δ = -43202-4·459000·0
Δ = 18662400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{18662400}=4320$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4320)-4320}{2*459000}=\frac{0}{918000}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4320)+4320}{2*459000}=\frac{8640}{918000}
=4/425
$