-12=-7-7/2*s

Solution for -12=-7-7/2*s equation:

-12=-7-7/2*s

We move all terms to the left:

-12-(-7-7/2*s)=0


Domain of the equation: 2*s)!=0

s!=0/1

s!=0

s∈R


We add all the numbers together, and all the variables

-(-7/2*s-7)-12=0

We get rid of parentheses

7/2*s+7-12=0

We multiply all the terms by the denominator


7*2*s-12*2*s+7=0

Wy multiply elements

14s*s-24s*s+7=0

Wy multiply elements

14s^2-24s^2+7=0

We add all the numbers together, and all the variables

-10s^2+7=0

a = -10; b = 0; c = +7;
Δ = b2-4ac
Δ = 02-4·(-10)·7
Δ = 280
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{280}=\sqrt{4*70}=\sqrt{4}*\sqrt{70}=2\sqrt{70}$
$s_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{70}}{2*-10}=\frac{0-2\sqrt{70}}{-20}
=-\frac{2\sqrt{70}}{-20}
=-\frac{\sqrt{70}}{-10}
$
$s_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{70}}{2*-10}=\frac{0+2\sqrt{70}}{-20}
=\frac{2\sqrt{70}}{-20}
=\frac{\sqrt{70}}{-10}
$