how do you solve a^2+8a+15=0 ?

a^2 +8a +15=0

you want to find two numbers that will multiply together to make 15 and the same to numbers should add to make 8. so in this case
5x3=15
5+3=8

so the answer is (a+5)(a+3)=0 if you multiply this out the braket then we get the original equation.

then from here we say that either a+5=0 or a+3=0
a=-5 or a=-3

( a + 5 ) ( a + 3 ) = 0

a = - 5 , a = - 3

a^2 + 8a + 15 = 0
a^2 + 5a + 3a + 15 = 0
(a^2 + 5a) + (3a + 15) = 0
a(a + 5) + 3(a + 5) = 0
(a + 5)(a + 3) = 0

a + 5 = 0
a = -5

a + 3 = 0
a = -3

∴ a = -5, -3

-3 and -5. u can factorize or just use the formula.

x=(-b +(b^2-4ac)^1/2)/2a and (-b -(b^2-4ac)^1/2)/2a

Solution:

a^2+8a+15=0
(a+3)(a+5)=0

a+3=0......a+5=0
a= -3...or......a= -5

a^2+8a+15 = 0 you can solve it by factorizing it
a^2 + 5a + 3a + 15 = 0
a(a + 5) + 3(a + 5) = 0
(a + 3) (a + 5) = 0
so a = - 3 or - 5 answer

You need to factorise as follows:
a^2+8a+15=(a+5)*(a+3)=0
Then it is clear that you have two solutions:
a=-3 (as this makes the right hand bracketed term equal to zero) or
a=-5 (as this makes the left hand bracketed term equal to zero)
Hope this helps!

a^2+8a+15=0
write 8a=3a+5a
thus we have
a^2+3a+5a+15=0
a(a+3)+5(a+3)=0
thus we have,
(a+3)(a+5)=0
hence a= -3 and-5

i hope this helpss thanx and may god bless u!!!!!!!!