49=7(3x-5)x=4

Solution for 49=7(3x-5)x=4 equation:

49=7(3x-5)x=4

We move all terms to the left:

49-(7(3x-5)x)=0


We calculate terms in parentheses: -(7(3x-5)x), so:

7(3x-5)x

We multiply parentheses

21x^2-35x

Back to the equation:

-(21x^2-35x)


We get rid of parentheses

-21x^2+35x+49=0

a = -21; b = 35; c = +49;
Δ = b2-4ac
Δ = 352-4·(-21)·49
Δ = 5341
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{5341}=\sqrt{49*109}=\sqrt{49}*\sqrt{109}=7\sqrt{109}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(35)-7\sqrt{109}}{2*-21}=\frac{-35-7\sqrt{109}}{-42}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(35)+7\sqrt{109}}{2*-21}=\frac{-35+7\sqrt{109}}{-42}
$