I.Trắc nghiệm
1. B
x - 2 = -5
x = -5 + 2
x = -3
2. A
12 - (6 - 18) = 12 - 6 + 18 = 6 + 18 = 24
3. D
$(-2)^{4}$ = $2^{4}$ = 16
4. C
5. D
6. B
7. A
8. A
9. D
II.Tự luận
Câu 1:
a, 3$\frac{1}{5}$ + 2$\frac{2}{3}$ = $\frac{16}{5}$ + $\frac{8}{3}$
= $\frac{48}{15}$ + $\frac{40}{15}$ = $\frac{88}{15}$
b, $\frac{-5}{11}$ + ($\frac{-6}{11}$ + 1) = $\frac{-5}{11}$ + $\frac{-6}{11}$ + 1 = $\frac{-11}{11}$ + 1 = -1 + 1 = 0
c, $\frac{5}{7}$ . $\frac{2}{11}$ + $\frac{5}{7}$ . $\frac{9}{11}$
= $\frac{5}{7}$ . ($\frac{2}{11}$ + $\frac{9}{11}$) = $\frac{5}{7}$ . $\frac{11}{11}$
= $\frac{5}{7}$ . 1 = $\frac{5}{7}$
d, ($\frac{-1}{4}$ + $\frac{5}{8}$) + $\frac{-3}{8}$ = ($\frac{-2}{8}$ + $\frac{5}{8}$) + $\frac{-3}{8}$ = $\frac{3}{8}$ + $\frac{-3}{8}$ = $\frac{0}{8}$ = 0
(xin hay nhất)
Chúc bạn học tốt!!!
