algebra
posted by Ami on .
if (6r  x) is on factors of 18r^2 + 12ry  3xr  2xy, what is the other factor.
a) 2y  3r
b) 3r + 2y
c) 3r  2x
d) 3r  2y

Arrange the polynomial in decreasing power of r:
18r^2 + 12ry  3xr  2xy
=18r² + (12y3x)r 2xy
Do a mental long division,
The first term is:
18r²/(6r) = 3r
The last term is:
2xy/(x) = 2y
Therefore the answer is 3r+2y.
Check:
(6rx)(3r+2y)
=18r² + (12y3x)r 2xy
The other factor is correct.