1、GRE（ QUANTITATIVE）练习试卷 1及答案与解析 1 What is the y-intercept of the line with the equation 2y=4x+6? 2 What is the slope of the line with the equation 3y=-2x+5? 3 What is the slope of the line x=4? 4 What is the equation of a line parallel to y=4x-12 that crosses the y-axis at 3? 5 What is the equation o
2、f a line perpendicular to 3x=2-y with the y-intercept 8? GRE（ QUANTITATIVE）练习试卷 1答案与解析 1 【正确答案】 First, rearrange the equation into the slope-intercept form by isolating y on the left side; divide both sides by 2: y=2x+3 You know that in the slope intercept formula, y=mx+b, b is the y-intercept. Beca
3、use b=3, the correct answer is 3. 2 【正确答案】 Rearrange the equation into the slope intercept form by isolating y on the left side; divide both sides by 3: You know that in the slope intercept formula, y=mx+b, m is the slope. Because the correct answer is 3 【正确答案】 This equation represents a vertical li
4、ne; the y-intercept is 0, so the line is parallel to the y-axis. A vertical line has an undefined slope, because the denominator is 0. 4 【正确答案】 For two lines to be parallel, their slopes must be equal; therefore, in the standard equation y=mx+b, m=4. You are given that the line crosses the y-axis at
5、 3, so the y-intercept (b) must be 3. If you substitute 4 for m and 3 for b in the standard equation, you get y=4x+3. 5 【正确答案】 First, rearrange the equation into slope-intercept form, by subtracting 3x and-y from both sides: y=-3x+2 For two lines to be perpendicular, their slopes must be negative reciprocals. The negative reciprocal of-3 is 1/3. The problem also states that the perpendicular line has a y-intercept of 8. If you substitute 1/3 for m and 8 for b in the standard equation, you get
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