Algebra
posted by Anonymous .
1. Subtract and simplify
18/y8  18/8y
2. subtract simplify if possible
v5/v  7v31/11v
3. Simplify by removing factors of 1
r^281/(r+9)^2
4. Divide and simplify
v^216/25v+100 divided by v4/20
5. find all rational numbers for which the rational expression is undefined:
18/7w
6. solve:
2/Z+4= 1/z6

1. 18 / (y  8)  18 / (8  y),
Multiply numerator and denominator of
2nd fraction by 1 and get:
18 / (y  8) + 18 / (y  8) =
36 / (y  8).
2. (v  5) / v  (7v  31) / 11v,
Common denominator = 11v:
(11v  55 7v + 31) / 11v,
Combine liketerms:
(4v  24) / 11v = 4(v  6) / 11v.
3. (r^2  81) / (r + 9)^2,
Factor the numerator:
(r + 9) (r  9) / (r + 9)^2,
Multiply numerator and denomjnator by
(r + 9)^2 and get:
(r + 9)^1 (r  9) / 1,
Multiply numerator and denominator by
(r + 9)^1:
(r  9) / (r + 9).
4. (v^2  (16/25)v + 100) / (v  4)/20
Multiply numerator and denominator by 25 and get:
(V^2  16V + 100) / 5(V  4) / 4,
Multiply numerator and denominqator by
4/5 and get:
4/5(v^2  16v + 100) / (v  4).
6. 2 / (z + 4) = 1 / (z  6),
Cross multiply:
2z  12 = z + 4,
2z  z = 4 + 12,
z = 16. 
_4y_____ _ ___3y________
y^2+6y+5 y^2+5y+4