Question

Bài 1:Thực hiện phép tính.

a.\(\left|-20\right|+40\)

b.4 + (-3) + 16

c.39 . 16 + 39 . 84 - 900

d.17\(^0\) + \([\)(135 - 130)\(^3\) - 5\(^{13}\) : 5\(^{11}\)\(]\)

Bài 2:Tìm số tự nhiên x, biết:

a. x + 20 = 55 - 35

b.\(\left|x\right|\) - 5 = 2015\(^0\)

Answer 1

Bài 1

a. \(\left|-20\right|+40=20+40=60\)

b. \(4+\left(-3\right)+16=4-3+16=1+16=17\)

c. \(39\cdot16+39\cdot84-900\)

\(=39\cdot\left(16+84\right)-900\)

\(=39\cdot100-900\)

\(=3900-900=3000\)

d. \(17^0+\left[\left(135-130\right)^3-5^{13}:5^{11}\right]\)

\(=17+\left[5^3-5^{13-11}\right]\)

\(=17+\left[125-5^2\right]\)

\(=17+\left[125-25\right]\)

\(=17+100=117\)

Bài 2

a. \(x+20=55-35\)

\(x+20=20\)

\(x=20-20\)

\(x=0\)

b. \(\left|x\right|-5=2015^0\)

\(\left|x\right|-5=1\)

\(\left|x\right|=1+5\)

\(\left|x\right|=6\)

\(\Rightarrow x=6\) hoặc \(x=-6\)