5r(13r+3s-5s^2) = 65r^2+15rs-25rs^2
-6s(13r+3s-5s^2) = -78rs-18s^2+30s^3
s^2(13r+3s-5s^2) = 13rs^2+3s^3-5s^4
Add them up to get
65r^2 - 63rs - 12rs^2 - 18s^2 + 33s^3 - 5s^4
Expand and simplify: (5r - 6s + s2) (13r + 3s - 5s2)
I got 65r^2-25rs^2+78rs+18s^2+3s^3+5s^4 but it's wrong?! Please correct me!
2 answers
(5r - 6s + s2) (13r + 3s - 5s2)
5r x 13r = 65r^2
5r x 3s = 15rs
5r x -5s^2 = -25rs^2
-6s x 13r = -78rs
-6s x 3s = -18s^2
-6s x -5s^2 = 30s^3
s^2 x 13r = 13rs^2
s^2 x 3s = 3s^3
s^2 x -5s^2 = -5s^4
Combined like terms:
-25rs^2 + 13rs^2 = -12rs^2
-78rs + 15rs = -63rs
30s^3 + 3s^3 = 33s^3
Answer:
-5s^4 + 33s^3 - 12rs^2 - 18s^2 - 63rs + 65r^2
5r x 13r = 65r^2
5r x 3s = 15rs
5r x -5s^2 = -25rs^2
-6s x 13r = -78rs
-6s x 3s = -18s^2
-6s x -5s^2 = 30s^3
s^2 x 13r = 13rs^2
s^2 x 3s = 3s^3
s^2 x -5s^2 = -5s^4
Combined like terms:
-25rs^2 + 13rs^2 = -12rs^2
-78rs + 15rs = -63rs
30s^3 + 3s^3 = 33s^3
Answer:
-5s^4 + 33s^3 - 12rs^2 - 18s^2 - 63rs + 65r^2
2 answers