Question

1) suppose y varies directly with x, and y=12 when x=-3, what is the value of y when x=6?

A) -24

B) 2

C) -2

D) -4


2) what is the equation of a line with a slop of -7 and a y-intercept of 6?


A) 6y = -7x

B) y = 6x + (-7)

C) -7y = x + 6

D) y = -7x + 6


3) what is the equation of the line through (5,1) with a slope of -3


A) y + 1 = 3(x + 5)

B) y - 1 = 3(x - 5)

C) y - 1 = -3(x - 5)

D) y + 1 = -3(x - 5)

4) what is the equation of the given line in point-slope form?

A) y - 1 = 2(x + 2)

B) y - 1 = 2(x - 2)

C) y - 2= 2(x - 1)

D) y - 2 = 1/2(x +2)
(graph below)

Answer 1

-24

Explanation:

Direct variation equation: y = kx, where k is the constant of variation.

Substituting the givens, we find k: 12 = k(-3), or k = -4. Then y = -4x.

If x = 6, this equation predicts that y will be -4(6) = -24