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Which equation represents line AB?

O y=4/3x-2/3
O y=4/3x+1/2
O y=3/4x-2/3
O y=3/4x+1/2

Which equation represents line AB? O y=4/3x-2/3 O y=4/3x+1/2 O y=3/4x-2/3 O y=3/4x-example-1

1 Answer

3 votes

Answer:

(d) y = 3/4x +1/2

Explanation:

You want the equation representing the line shown in the graph.

Slope-intercept equation

The line is shown between points A(-2, -1) and B(6, 5). The slope can be found using the slope formula:

m = (y2 -y1)/(x2 -x1)

m = (5 -(-1))/(6 -(-2)) = 6/8 = 3/4

The y-intercept can be found using the formula ...

b = y1 -m(x1)

b = -1 -(3/4)(-2) = 1/2

Then the slope-intercept equation is ...

y = mx +b

y = 3/4x +1/2

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Additional comment

The line crosses the y-axis between y=0 and y=1, so you know the y-intercept is positive. This eliminates answer choices A and C.

The y-value of 5 corresponding to the x-value of 6 (at point B) tells you the slope of the line is less than 5/6. This eliminates answer choices A and B.

The only viable answer choice is D, which is the correct one.

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User Gustavo Gondim
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