Multiply both sides by -8 to get k = -16
To check the solution, plug in -16 into the original equation. You do in-fact get 2
I don't know about the first one but for the second one:

Answer: the length of the rectangle is 12 inches
Step-by-step explanation:
Let the length of the rectangle is x inches
Hence, the width is (x/2)+4 inches
Thus,
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Divide both parts of the equation by 3:

Answer:
y-7=-4(x+2)
Step-by-step explanation:
y-y1=m(x-x1)
y-7=-4(x-(-2))
y-7=-4(x+2)