y2-7y+4=0

Solution for y2-7y+4=0 equation:

y2-7y+4=0

We add all the numbers together, and all the variables

y^2-7y+4=0

a = 1; b = -7; c = +4;
Δ = b2-4ac
Δ = -72-4·1·4
Δ = 33
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{33}}{2*1}=\frac{7-\sqrt{33}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{33}}{2*1}=\frac{7+\sqrt{33}}{2}
$