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

=49+60=109

\(\dfrac{4}{13}+\dfrac{-\left(-12\right)}{39}\)

\(=\dfrac{4}{13}+\dfrac{12}{39}\)

\(=\dfrac{12}{39}+\dfrac{12}{39}\)

\(=\dfrac{24}{39}\)

\(=\dfrac{8}{13}\)

= 

Chọn

Không biết <=> Không làm 

= x mũ 2 + 3

\(\left(x^3+4x^2+3x+12\right):\left(x+4\right)\\ =\left[x^2\left(x+4\right)+3\left(x+4\right)\right]:\left(x+4\right)\\ =\left[\left(x^2+3\right)\left(x+4\right)\right]:\left(x+4\right)\\ =x^2+3\)

\(=x^2+3\)

80 – [130 – (12 - 4)2] = 80 – [130 – 82]

= 80 – [130 - 64] = 80 - 66 = 14

\(\begin{array}{l}\frac{{ - 4}}{3} - \frac{{12}}{5} = \frac{{ - 4}}{3} + \frac{{ - 12}}{5}\\ = \frac{{ - 20}}{{15}} + \frac{{ - 36}}{{15}} = \frac{{ - 56}}{{15}}\end{array}\).

Lời giải:
\(\frac{20^4.15^5}{12^5.25^4}=\frac{(2^2.5)^4.(3.5)^5}{(2^2.3)^5.(5^2)^4}=\frac{2^8.5^4.3^5.5^5}{2^{10}.3^5.5^8}\)

\(=\frac{2^8.5^9.3^5}{2^{10}.3^5.5^8}=\frac{2^8.5^8.5.3^5}{2^8.2^2.3^5.5^8}=\frac{5}{2^2}=\frac{5}{4}\)

=11+(-7).12+(-48):(-4)+25

=11+(-84)+12+25

=-73+12+25

= -61+25

=-36

11 + (- 7) . 12 + (- 48) : (- 4) + 5²

= 11 + (- 84) + 12 + 25

= - 73 + 37

= - 36