Answer: Choice A
y = (-3/4)(x + 4) + 6
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Let's go through the answer choices
- Choice A is something we'll come back to
- Choice B is false because the line does not go uphill as we move from left to right. The graphed line has a negative slope, which contradicts what choice B is saying.
- Choice C is false for similar reasons as choice B. The slope should be negative.
- Choice D has a negative slope, but the y intercept is wrong. The y intercept should be 3. So choice D is false as well.
We've eliminated choices B through D.
Choice A must be the answer through process of elimination.
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Here's an alternative method:
If we started at a point like (0,3) and move to (4,0), note how the slope is -3/4
This is because we've moved down 3 units and to the right 4 units.
m = slope = rise/run = -3/4
We can also use the slope formula m = (y2-y1)/(x2-x1) to see this.
Then we pick on a point that is on the diagonal line. It could be any point really, but the point your teacher used for choice A is (x1,y1) = (-4,6)
So,
y - y1 = m(x - x1)
y - 6 = (-3/4)(x - (-4))
y - 6 = (-3/4)(x + 4)
y = (-3/4)(x + 4) + 6
