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 6道SAT2数学练习题目
 1.What is the closest approximation of the solution of the equation 2x - 1 = 3x + 1? 　　(a) -4.42 　　(b) -5.81 　　(c) -3.22 　　(d) 4.93 　　(e) 3.33 　　Explanation： 　　log(2x - 1) = log(3x + 1) (x - 1)log2 = (x + 1)log3 x(log2 - log3) = log3 + log2 x = (log3 + log2)/(log2 - log3) x is aprox. = -4.418 　　2. What is the range of (x - y) if 3 < x < 4 and -2 < y< -1? 　　(a) 4< x-y <5 　　(b) 1< x-y <3 　　(c) 1< x-y <5 　　(d) 4< x-y <6 　　(e) 3< x-y <6 　　Explanation： 　　We can determine the range of -y: 1 < -y < 2 　　We determine the range of x-y by adding the ranges of x and -y: Therefore, 4< x-y <6 　　3.A bus travels the distance d from New York to Boston. t1 hours after the bus left New York, a car starts to travel the same distance d from New York to Boston. Both vehicles reach Boston at the same time. Find an expression for d as a function of t1, the speed of the bus v1 and the speed of the car v2. 　　(a) d = v1t1/(v2 - v1) 　　(b) d = v1v2t1/(v2 - v1) 　　(c) d = v1t1/(v2 + v1) 　　(d) d = v1v2t1/(v2 + v1) 　　(e) d = v1v2t1 　　Explanation： 　　If t is the duration of the travel of the bus, d = v1t d = v2(t - t1) Therefore, v1t = v2(t - t1) t = v2t1 / (v2 - v1) d = v1v2t1 / (v2 - v1) 　　4.Find the value of x if: x + y + z = 5 x + y - z = 3 x - y = 2 　　(a) -3 　　(b) -1 　　(c) 1 　　(d) 3 　　(e) 5 　　Explanation： 　　We notice that if we add equations 1 and 2 we can eliminate z: x + y + z + x + y - z = 5 + 3 2・(x + y) = 8 x + y = 4 At this point we have a system of 2 linear equations with 2 variables, x and y: x - y = 2 x + y = 4 If we add these 2 equations, we get 2・x = 6 and x = 3. 　　5.A camera has a price of 300 dollars. Its price is lowered 10% and then increased 10%. What is the final selling price of the camera? 　　(a) \$297 　　(b) \$303 　　(c) \$310 　　(d) \$330 　　(e) \$303 　　Explanation： 　　After it is lowered by 10%, the price is \$300 - \$30 = \$270. A 10% increase of a \$270 price is \$27, so the final price is \$270 + \$27 = \$297. 　　6.The equation 2x2 - 2x - 60 = 0 has the following 2 solutions: 　　(a) {-5, 5} 　　(b) {5, -6} 　　(c) {-5, -6} 　　(d) {-5, 6} 　　(e) {5, 6} 　　Explanation： 　　2x2 - 2x - 60 = 0 x2 - x - 30 = 0 The sum of the solutions is 1 and the product is -30 so the solutions are {-5, 6} 　　以上就是这6道SAT2数学练习题目的全部内容，难度不是很大，都是代数方面的题目。大家在备考SAT2数学考试的是，如果能够把记忆词汇和练习题目结合到一起，就可以非常好理解题目的含义并且进行应对了。