Question what-i

1.1 Linear Functions - Parallel/perpendicular line relationships
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What is the equation of the line that passes through the point 0,5 and is parallel to the graph of y = 7 x + 4 in the xy-plane?

A.

y = 5 x

B.

y = 7 x + 5

C.

y = 7 x

D.

y = 5 x + 7

What is the equation of the line that passes through the point 0 , 5 and

Medium-difficulty · SAT Math · Linear Functions — Parallel/perpendicular line relationships. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

Choice B is correct. The equation of a line in the xy-plane can be written in slope-intercept form y = m x + b , where m is the slope of the line and 0,b is its y-intercept. It’s given that the line passes through the point 0,5. Therefore, b = 5 . It’s also given that the line is parallel to the graph of y = 7 x + 4 , which means the line has the same slope as the graph of y = 7 x + 4 . The slope of the graph of y = 7 x + 4 is 7 . Therefore, m = 7 . Substituting 7 for m and 5 for b in the equation y = m x + b yields y = 7 x + 5 .

Choice A is incorrect. The graph of this equation passes through the point 0,0, not 0,5, and has a slope of 5 , not 7 .

Choice C is incorrect. The graph of this equation passes through the point 0,0, not 0,5.

Choice D is incorrect. The graph of this equation passes through the point 0,7, not 0,5, and has a slope of 5 , not 7 .