How do you solve #x^2+7x+10=0#?
We could right the equation in another form using brackets.
In order to get two numbers to multiply and give 0, at least one number has to be 0.
a stands for the first bracket and b for the second.
a x b = 0
a=0 or b=0 to make this equation valid.
Therefore x= -2 or x= -5 because -2+2=0 and -5+5=0 according to both brackets.