Help with number 70
Step by step please

Answer:
r^2 +s^2 = 34
Step-by-step explanation:
(r+s) ^2
We can FOIL
first = r*r = r^2
outer r*s =rs
inner = s*r =rs
last = s*s =s^2
Add them together
r^2 +2rs + s^2
(r+s) ^2 = r^2 +2rs+s^2 = 64
We are given that rs = 15
so 2*rs = 2 (15) = 30
r^2 +30 + s^2 = 64
Subtract 30 from each side
r^2 +30-30 + s^2 = 64-30
r^2 +s^2 = 34
Answer:
Step-by-step explanation:
We know:
[tex](r+s)^2=r^2+2rs+s^2[/tex]
We have:
[tex]rs=15\\\\(r+s)^2=64[/tex]
Substitute:
[tex]64=r^2+2(15)+s^2[/tex]
[tex]64=r^2+30+s^2[/tex] subtract 30 from both sides
[tex]34=r^2+s^2[/tex]