GED Mathematical Reasoning Preparation Course:Expressions, equations and inequalities
不限时专题测验:关于Expressions, equations and inequalities的17道题,每道题作答后都有解释。每次题目和选项都会重新打乱。
专题测验5:Expressions, equations and inequalities
-
第1题,共17题
显示答案
答案: A. 21
3(−2)² = 3 × 4 = 12. −2(−2) = +4. Then 12 + 4 + 5 = 21.
-
第2题,共17题
显示答案
答案: A. 65 + 90h
The $65 is charged once, and the $90 is charged for each of the h hours: 65 + 90h.
-
第3题,共17题
显示答案
答案: A. 2x + 22
Distribute: 4x + 12 − 2x + 10. Note that −2 × −5 = +10. Combine: 2x + 22.
-
第4题,共17题
显示答案
答案: B. x = 8
Subtract 3x from both sides: 2x − 7 = 9. Add 7: 2x = 16. Divide by 2: x = 8.
-
第5题,共17题
显示答案
答案: C. 23
Let the numbers be n, n + 1 and n + 2. Then 3n + 3 = 72, so 3n = 69 and n = 23.
-
第6题,共17题
显示答案
答案: C. 150
Set 30 + 0.10m = 45. Then 0.10m = 15, so m = 150 minutes.
-
第7题,共17题
显示答案
答案: D. 8
Add the two equations: 2x = 16, so x = 8. Then y = 12 − 8 = 4.
-
第8题,共17题
显示答案
答案: B. 10
Let a + c = 20 and 12a + 7c = 190. Replace c with 20 − a: 12a + 140 − 7a = 190, so 5a = 50 and a = 10.
-
第9题,共17题
显示答案
答案: A. x > 5
Add 4: 3x > 15. Divide by 3 (a positive number, so the sign stays): x > 5.
-
第10题,共17题
显示答案
答案: C. x ≥ −4
Subtract 6: −2x ≤ 8. Dividing by −2 flips the sign: x ≥ −4.
-
第11题,共17题
显示答案
答案: B. 10
Write 15 + 4.50n ≤ 60. Then 4.50n ≤ 45, so n ≤ 10. He can buy at most 10 snacks.
-
第12题,共17题
显示答案
答案: A. 2x² − 5x − 12
Multiply each term: 2x·x = 2x², 2x·(−4) = −8x, 3·x = 3x, 3·(−4) = −12. Combine: 2x² − 5x − 12.
-
第13题,共17题
显示答案
答案: A. (x + 7)(x − 2)
Find two numbers that multiply to −14 and add to 5: 7 and −2. So x² + 5x − 14 = (x + 7)(x − 2).
-
第14题,共17题
显示答案
答案: D. x − 4
x² − 16 is a difference of squares: (x + 4)(x − 4). Divide out (x + 4) to get x − 4.
-
第15题,共17题
显示答案
答案: D. x = 2 or x = 4
Factor: (x − 2)(x − 4) = 0. A product is 0 only if a factor is 0, so x = 2 or x = 4.
-
第16题,共17题
显示答案
答案: B. x = 1/2 or x = −2
a = 2, b = 3, c = −2. b² − 4ac = 9 + 16 = 25. x = (−3 ± 5) ÷ 4, so x = 2/4 = 1/2 or x = −8/4 = −2.
-
第17题,共17题
显示答案
答案: C. t = d/r
Divide both sides of d = rt by r: t = d/r. For example, 120 miles at 60 mph takes 2 hours.
键盘:按1–4作答,按 Enter 进入下一题。
真实考试:145 on each GED subject