SAT数学练习题答案解析Question 7:
Answer: log(x2y3) = log(x2) + log(y3) = 2log(x) + 3log(y) = 4 + 15 = 19
SAT数学练习题答案解析Question 8:
Answer: 17 = 17·1
81 = 3·3·3·3·1
The correct answer is (a).
SAT数学练习题答案解析Question 9:
Answer:
y + x = 5 can be written as y = -x + 5. The slope of this equation is m1 = -1.
y - x = 5 can be written as y = x + 5. The slope of this equation is m2 = 1.
m2 = -1/m1 so the 2 lines are perpendicular.
We also need to find where the 2 lines intersect. If we add the 2 equations, 2·y = 10, y = 5
From the first equation, x = 5 - y = 5 - 5 = 0. In conclusion the lines intersect at (0, 5) and this point is on the y axis.
In conclusion I and II statements are correct.
SAT数学练习题答案解析Question 10:
Answer:
From the numerator of the fraction, -x should be positive or equal to zero, so x<=0.
x cannot take the values x = 2 and x = -2, so the domain of the function is (-∞ , -2) U ( -2 , 0]
要想SAT2数学成绩有所提高，坚持每天做练习是十分必要的，就像这样每天完成SAT2数学Level 2练习题，并进行总结，日积月累，成绩就会有明显地提高。
