(7x+2)(7x+5)=0

Solution for (7x+2)(7x+5)=0 equation:

(7x+2)(7x+5)=0

We multiply parentheses ..

(+49x^2+35x+14x+10)=0

We get rid of parentheses

49x^2+35x+14x+10=0

We add all the numbers together, and all the variables

49x^2+49x+10=0

a = 49; b = 49; c = +10;
Δ = b2-4ac
Δ = 492-4·49·10
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(49)-21}{2*49}=\frac{-70}{98}
=-5/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(49)+21}{2*49}=\frac{-28}{98}
=-2/7
$