\(142-\left[50-\left(2^3×10-2^3×5\right)\right]\)

\(=142-\left[50-\left(8×10-8×5\right)\right]\)

\(=142-\left[50-\left(80-40\right)\right]\)

\(=142-\left[50-40\right]\)

\(=142-10\)

\(=132\)

142-[50-(8 x 10 - 8 x5)]

142-{50-[8 x(10-5)}

142-{50-8 x 5}

142-{50-40}

142-10

132

thcs và thpt: dấu nhân luôn luôn phải dùng dấu chấm!

3³ : 3¹³ + 50 : 5² = 3^-10 + 25 =  \(\frac{1}{59049}\) + 25 = \(\frac{1476226}{59049}\)

\(2.5^2-176:2^3\)

\(=\left(2.25\right)-\left(176:8\right)\)

\(=50-22\)

\(=28\)

\(2,5^2-176:2^3\)

\(=\frac{25}{4}-22\)

\(=\frac{-63}{4}\)

\(2\cdot5^2-176:2^3\)

\(=2\cdot25-176:8\)

\(=50-22\)

\(=28\)

a, = 77

b, =25

trình bày đàn hoàn nhé bạn tớ kick cho

k đi rồi nói

\(a)\)\(\left(50-6.x\right).18=2^3.3^2.5\)

\(\Leftrightarrow\)\(\left(50-6.x\right).18=8.9.5\)

\(\Leftrightarrow\)\(\left(50-6.x\right).18=360\)

\(\Leftrightarrow\)\(\left(50-6.x\right)=360\div18\)

\(\Leftrightarrow\)\(50-6.x=20\)

\(\Leftrightarrow\)\(6.x=50-20\)

\(\Leftrightarrow\)\(6.x=30\)

\(\Leftrightarrow\)\(x=5\)

\(b)\)\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=7450\)

\(\Leftrightarrow\)\(100x+\left(1+2+3+...+100\right)=7450\)

\(\Leftrightarrow\)\(100x+5050=7450\)

\(\Leftrightarrow\)\(100x=7450-5050\)

\(\Leftrightarrow\)\(100x=2400\)

\(\Leftrightarrow\)\(x=24\)

b.

(x+1)+(x+2)+...+(x+100)=7450

=> 100x + (1+2+3+...+100)=7450

=>100x + (100+1).50=7450

=>100x=2400

=>x=24

(x+1)+(x+2)+(x+3)+....(x+100)=7450

=> 100x + (1+2+3...+100)=7450

=> 100x + 5050=7450

=> 100x =7450-5050

=> 100x = 2400

=> x= 24