下面是两道关于代数方面的
1.Which of the following lines is perpendicular to y = 3x + 4 and has 6 for its x-intercept? (A)y = 3x – 6 (B)y = –3x + 6 (C)y = – x + 6 (D)y = – x – 2 (D)y = – x + 2 Correct Choice:E Explanation:The slope of y = 3x + 4 is 3. A line perpendicular to this line has a slope that is the opposite of the reciprocal of 3, or –1⁄3. If the x-intercept of the desired line is 6, then the line contains the point (6, 0), and we have enough information to put it in point-slope form: (y – 0) = –1⁄3(x – 6). This simplifies to y = –1⁄3 x + 2. The following equation represents which type of graph? 2y = –6x2+ 24x – 12 (A)A parabola that opens downward with vertex (–2 ,6) (B)A parabola that opens upward with vertex (6, 2) (C)A parabola that opens upward with vertex (–2, –6) (D)A parabola that opens downward with vertex (2, 6) (D)A parabola that opens downward with vertex (–6, 2) Correct Choice:D In this equation, y is raised to the first power, and x is squared. This should lead you to believe that the graph of this equation is a parabola (in the equation of a circle, both variables are squared). Simplify the equation to arrive at the standard form: 2y=-6x2+24x-12 Y=-3x2+12x-6 Y=-3(x2-4x)-6 Y=-3(x2-4x+4)-6+12 Y=-3(x-2)2+6
The equation in the question is the standard form of a parabola. From it we can see that –3 < 0, so the parabola opens downward, and the vertex is (2, 6).
以上就是这两道SAT数学试题及其解法的全部内容，非常详细，对于每一道题都进行了答案的解析。大家可以在备考SAT数学中关于代数部分的时候，对上面的这两道题的类型进行掌握。这样大家就能更加轻松的应对SAT考试了。