Đặt \(A=1+7+7^2+...7^{50}\)

\(7\cdot A=7+7^2+7^3+.....+7^{51}\)

\(7\cdot A-A=\left(7+7^2+7^3+.....+7^{51}\right)-\left(1+7+7^2+....+7^{50}\right)\)

\(A.\left(7-1\right)=\left(7-7\right)+\left(7^2-7^2\right)+.....+\left(7^{50}-7^{50}\right)+7^{51}-1\)

\(A\cdot6=7^{51}-1\Rightarrow A=\frac{7^{51}-1}{6}\)

\(48\div4+3^9\div3^7+5^0\)

\(=12+9+1\)

\(=22\)

\(\left(5^{19}\div5^{17}+3\right)\div7\)

\(=\left(25+3\right)\div7\)

\(=28\div7\)

\(=4\)

\(295-\left(32-2^2\times5\right)^2\)

\(=295-144\)

\(=151\)

\(6^2\div9+50\times2-3^3\times3\)

\(=36\div9+100-27\)

\(=4+100-27\)

\(=100-27\)

\(=73\)

\(48:4+3^9:3^7+5^0\)

\(=12+3^{9-7}+1\)

\(=12+9+1\)

\(=22\)

\(\left(5^{19}:5^{17}+3\right):7\)

\(=\left(5^{19-17}+3\right):7\)

\(=\left(5^2+3\right):7\)

\(=\left(25+3\right):7\)

\(=28:7\)

\(=4\)

\(295-\left(31-2^2\cdot5\right)^2\)

\(=295-\left(31-4\cdot5\right)^2\)

\(=295-\left(31-20\right)^2\)

\(=295-11^2\)

\(=295-121\)

\(=174\)

\(6^2:9+50\cdot2-3^3\cdot3\)

\(=36:9+50\cdot2-3^4\)

\(=4+100-81\)

\(=23\)

\(48:4+3^9:3^7+5^0=12+3^2+1=12+9+1=22\)

\(\left(5^{19}:5^{17}+3\right):7=\left(5^2+3\right):7=\left(25+3\right):7=28:7=4\)

\(295-\left(31-2^2.5^2\right)=295-\left(31-10^2\right)=295-\left(31-100\right)=295-\left(-69\right)=364\)

\(6^2:9+50.2-3^3.3=36:9+100-3^2=4+100-9=95\)

a. 50-17+2-50+15

= (50-50)+(15+2-17)

= 0+0 = 0

a.0

b.79
c.16400
d.10

Lời giải:

$10+2.4^2=10+2.16=10+32=42$

Đáp án A

$50-4.3^2=50-4.9=50-36=14$

Đáp án A.

a, 103

b, 6

c, 8

d,21

Bạn có thể đọc cách cộng trừ các số nguyên trong sgk Toán 6 tập 1 nhé!

1) 5 + (-4) = 1

2) (-8) + 2 = -6

3) 8 + (-2) = 6

4) 11 + (-3) = 8

5) (-11) + 2 = -9

6) (-7) + 3 = -4

7) (-5) + 5 = 0

8) 11 + (-12) = -1

9) (-18) + 20 = 2

10) (15) + (-12) = 3

11) (-17) + 17 = 0

12) 16 + (-2) = 14

13) (30) + (-14) = 16

14) (-19) + 20 = 1

15) (-18) + 15 = -3

16) (10) + (-6) = 4

17) (-28) + 14 = -14

18) 15 + (-30) = -15

19) (15) + (-4) = 11

20) (-21) + 11 = -10

21) 8 + (-22) = -14

22) (-15) + 4 = -11

23) (-3) + 2 = -1

24) 17 + (-14) = 3

25) 17 + (-14) = 3

thế này đọc đc mới đỉnh

\(98.42-50\left[\left(18-2^3\right):2+3^2\right]\\ =4116-50\left[\left(18-8\right):2+9\right]\\ =4116-50\left[10:2+9\right]\\ =4116-50\left[5+9\right]\\ =4116-50.14\\ =4116-700\\ =3416\)

98.42-50.[(18-2³):2 +3²]

=98.42-50.[(18-8):2+3²]

=98.42-50.[10:2+3]

=98.42-50.[5+3]

=98.42-50.8

= 4116-400

=3716

=98*42-50*[(18-8):2+9]

=98*42-50*14

=3416

\(a.\sqrt{\left(\sqrt{2}-\sqrt{3}\right)^2}+\sqrt{18}=\left|\sqrt{2}-\sqrt{3}\right|+3\sqrt{2}=\sqrt{3}-\sqrt{2}+3\sqrt{2}\left(\sqrt{3}>\sqrt{2}\right)=\sqrt{3}+2\sqrt{2}\)\(b.3\sqrt{2}-4\sqrt{18}+2\sqrt{32}-\sqrt{50}=3\sqrt{2}-12\sqrt{2}+8\sqrt{2}-5\sqrt{2}=-6\sqrt{2}\)

a: \(=\sqrt{3}-\sqrt{2}+3\sqrt{2}=2\sqrt{2}+\sqrt{3}\)