45 + 6 x 17 + 55 + 2 x 3 x 83 
= 45 + 102  +  55 + 6 x 38 
= 45 + 102 + 55 + 228 
= 147 + 55 + 228 
= 202 + 228 
= 430

430

Lời giải:
$(-55).(-17)-55.(-2+17)=(-55)(-17)-55.15=(-55)(-17)+(-55).15$

$=(-55)(-17+15)=(-55).(-2)=55.2=110$

Câu 2: 

\(\dfrac{7}{9}\cdot\dfrac{3}{35}=\dfrac{1}{5}\cdot\dfrac{1}{3}=\dfrac{1}{15}\)

\(\dfrac{9}{22}\cdot55=\dfrac{9\cdot55}{22}=\dfrac{9\cdot5}{2}=\dfrac{45}{2}\)

\(\frac{7}{9}\cdot\frac{3}{5}=\frac{7\cdot3}{9\cdot5}=\frac{7\cdot1}{3\cdot5}=\frac{7}{15}\)

\(\frac{9}{22}\cdot55=\frac{9}{22}\cdot\frac{55}{1}=\frac{9\cdot55}{22\cdot1}=\frac{9\cdot5}{2\cdot1}=\frac{45}{2}\)

\(\frac{11}{17}:\frac{33}{34}=\frac{11}{17}\cdot\frac{34}{33}=\frac{11\cdot34}{17\cdot33}=\frac{1\cdot2}{1\cdot3}=\frac{2}{3}\)

224400

Lời giải:
$55\times 17\times 16\times 15=224400$

(12000+X):376=X

12000+X=376 x X

12000=376 x X - X

12000=375 x X

X=12000:375= 32

a.

\(3-\left(17-x\right)=289-\left(36+289\right)\)

\(3-17+x=289-36-289\)

\(x=\left(289-289\right)+\left(-36-3+17\right)\)

\(x=-22\)

b.

\(x-73=\left(-35\right)+\left|-55\right|\)

\(x-73=-35+55\)

\(x=-35+55+73\)

\(x=93\)

c.

\(\left|x\right|-3=2\)

\(\left|x\right|=3+2\)

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

\(x=\pm5\)

Vậy x = 5 hoặc x = -5

d.

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

\(x+1=\pm5\)

TH1:

\(x+1=5\)

\(x=5-1\)

\(x=4\)

TH2:

\(x+1=-5\)

\(x=-5-1\)

\(x=-6\)

Vậy x = 4 hoặc x = -6

a, \(3-17+x=289-36-289\)

\(\Rightarrow x-14=-36\)

\(\Rightarrow x=-22\)

\(b,x-73=\left(-35\right)+\left|-55\right|\)

\(\Rightarrow x-73=\left(-35\right)+55\)

\(\Rightarrow x-73=20\)

\(\Rightarrow x=93\)

\(c,\left|x\right|-3=2\)

\(\Rightarrow\left|x\right|=5\)

\(\Rightarrow x=\pm5\)

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

\(\Rightarrow\) \(\left[\begin{array}{nghiempt}x+1=5\\x+1=-5\end{array}\right.\) \(\Rightarrow\) \(\left[\begin{array}{nghiempt}x=4\\x=-6\end{array}\right.\)