Can you check my answers?

Question

1. Table modeling a linear relationship is shown below. What is the rate of change of nails to birdhouses?

2 birdhouses to 22 nails
3 birdhouses to 33 nails
4 birdhouses to 44 nails
5 birdhouses to 55 nails

a. 55 nails per birdhouse
b. 2 nails per birdhouse
c. 22 nails per birdhouse
d. 11 nails per birdhouse

Ans: D (change in nails is 11 and change in birdhouses is 1, 11/1)

4. Which of the following is true about the functions f(x) and g(x)?

f(x) = 2/3x - 6

(table below):
x --- g(x)
-4 ... 10
0 ... 7
4 ... 4
8 ... 1

a. Rate of change of f(x) is less than rate of change of g(x).
b. Rate of change of f(x) is greater than rate of change of g(x).
c. The y-intercept of f(x) is equal to the rate of change of g(x).
d. The y-intercept of f(x) is greater than the rate of change of g(x).

Ans: B (b/c rate of change of g(x) is -3, rate of change of f(x) is +4 and y intercept of f(x) is -6).

10. Which equation represents the line that passes through the point (1,5) and has a slope of -2?

a. y = -2x + 7
b. y = -2x + 11
c. y = 2x - 9
d. y = 2x +3

Ans: A (b/c m=-2; solve for by substitute 1 in for x and substitute 5 in for y. get 5 = -2(1) + b, add +2 to both sides, 7 = b)

1. If f(x)= 3x + 1 and g(x) = 4x-8, find f(1) + g(-2).

a. -2
b. 4
c. 9
d. -11

Ans: Didn't get any of those answers. f(x) = 3(1) + 1 = 4
g(x) = 4(-2) - 8 = -16; 4 + -16 = -12

2. Let g(x) = x^2 - 3x +1. Find g(2).

a. 11
b. -4
c. -1
d. -3

Ans: C (2^2 - 3(2) + 1 = 4-6+1 = -1)

Answer 1

1. If f(x)= 3x + 1 and g(x) = 4x-8, find f(1) + g(-2).

a. -2
b. 4
c. 9
d. -11

I agree with you - none of the above but -12

I agree with the rest also

Answer 2

#1 D is correct
#4 B is correct, but the rate of change of f is 2/3, and of g is -3/4
#10 A is correct

#1 I agree. Must be a typo.
f(1)+g(2) = 4, however
#2 C is correct

Answer 3

Hi Steve,

How do you get the rate of change of 2/3 and -3/4 for problem #4?