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

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

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

We move all terms to the left:

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


Domain of the equation: 8x!=0

x!=0/8

x!=0

x∈R



Domain of the equation: 40x!=0

x!=0/40

x!=0

x∈R


We add all the numbers together, and all the variables

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

We calculate fractions


1280x^2/8000x^2+(-7000x)/8000x^2+(-1800x)/8000x^2+72=0

We multiply all the terms by the denominator


1280x^2+(-7000x)+(-1800x)+72*8000x^2=0

Wy multiply elements

1280x^2+576000x^2+(-7000x)+(-1800x)=0

We get rid of parentheses

1280x^2+576000x^2-7000x-1800x=0

We add all the numbers together, and all the variables

577280x^2-8800x=0

a = 577280; b = -8800; c = 0;
Δ = b2-4ac
Δ = -88002-4·577280·0
Δ = 77440000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{77440000}=8800$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8800)-8800}{2*577280}=\frac{0}{1154560}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8800)+8800}{2*577280}=\frac{17600}{1154560}
=5/328
$