1. Mr. Lui wrote 15 - 5x/x^2 - 9x + 18.

Question

a. Explain what kind of expression it is.
b. Simplify the expression. Show your work.
c. Identify any excluded values.

A:

a. It is a rational expression.
b. 5/x - 6
c. Excluded value: x = 6

2. Lynne can paint a wall in 40 minutes. Jeff can paint the same wall in 60 minutes. How long will it take Lynne and Jeff to paint the wall if they work together?

A: ?

3. What are 2 values of b that will make 2x^2 - bx - 20 factorable? Explain your answer.

A: ?

Answer 1

1.(15-5x)/(x^2-9x+18).
-5(x-3)/(x-3)(x-6) = -5/(x-6).

2. T=T1*T2/(T1+T2)
T = 40*60/(40+60)=24 min.

3. A*C = 2*(-20)-40 = 4*(-10) = 5*(-8)
B = The sum of the pair of factors that
are divisible by 2:
B = 2+(-20) = -18
B = 4+(-10) = -6

Eq1: 2x^2-18x-20 = 0
Divide by 2:
x^2-9x-10 = 0
(x+1)(x-10) = 0

Eq2: 2x^2-6x-20 = 0
Divide by 2 and factor.


9

Answer 2

Henry is right the way he explained it