Which statements give the correct constant of proportionality as y = kx?
Choose the correct answers.

1) It takes 5 cans of paint (x) to cover 10 dog houses (y).
y = 2x

2)A lawn service charges $258(y) for mowing 6 yards (x).
y = $43x

3)8 pounds of beef (x) costs $78 (y).
y = $9x

4)Beverly can reads 315 pages (y) in 7 hours (x).
y = 45x

5)10 chocolate bars ( x) contain 3,330 calories (y).
y = 333x

answer:

sometimes

*i think

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3