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Mathematics>Standard Multiple Choice

Read the following SAT test question and then click on a button to select your answer.

Which of the following equations represents a line in the x y-plane with an x-intercept (-2,0) and a slope of 4?

A.y=4x+8
B.y=-4x+8
C.y=4x-2
D.y=-4x-2

答案和解析

答案：A

解析：

Option A is correct. If the slope of the line is 4, then an equation for it would be in the form y=4x+b. Then, substituting the x- and y-coordinates of the given point to satisfy the equation yields 0=4(-2)+b. Solving for b yields b=8, so an equation that represents the given conditions is y=4x+8.