1.2(x+5)=1.6x(2x+5)

Solution for 1.2(x+5)=1.6x(2x+5) equation:

1.2(x+5)=1.6x(2x+5)

We move all terms to the left:

1.2(x+5)-(1.6x(2x+5))=0

We multiply parentheses

1.2x-(1.6x(2x+5))+6=0


We calculate terms in parentheses: -(1.6x(2x+5)), so:

1.6x(2x+5)

We multiply parentheses

2x^2+5x

Back to the equation:

-(2x^2+5x)


We get rid of parentheses

-2x^2+1.2x-5x+6=0

We add all the numbers together, and all the variables

-2x^2-3.8x+6=0

a = -2; b = -3.8; c = +6;
Δ = b2-4ac
Δ = -3.82-4·(-2)·6
Δ = 62.44
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3.8)-\sqrt{62.44}}{2*-2}=\frac{3.8-\sqrt{62.44}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3.8)+\sqrt{62.44}}{2*-2}=\frac{3.8+\sqrt{62.44}}{-4}
$