\(3-3x-\left(\dfrac{5}{4}-\dfrac{7}{5}\right)=\dfrac{9}{20}\)

\(3-3x-\left(\dfrac{25}{20}-\dfrac{28}{20}\right)=\dfrac{9}{20}\)

\(3-3x-\dfrac{-3}{20}=\dfrac{9}{20}\)

\(3-3x=\dfrac{9}{20}+\dfrac{-3}{20}=\dfrac{6}{20}=\dfrac{3}{10}\)

\(3x=3-\dfrac{3}{10}=\dfrac{30}{10}-\dfrac{3}{10}=\dfrac{27}{10}\)

\(x=\dfrac{27}{10}:3=\dfrac{27}{10}.\dfrac{1}{3}\)

\(x=\dfrac{27}{30}=\dfrac{9}{10}\)

\(\dfrac{2}{9}.\left[\dfrac{-4}{45}:\left(\dfrac{1}{5}-\dfrac{2}{15}\right)+\dfrac{5}{3}\right]-\dfrac{-5}{27}\)

\(\dfrac{2}{9}.\left[\dfrac{-4}{45}:\left(\dfrac{3}{15}-\dfrac{2}{15}\right)+\dfrac{5}{3}\right]-\dfrac{-5}{27}\)

\(\dfrac{2}{9}.\left(\dfrac{-4}{45}:\dfrac{1}{15}+\dfrac{5}{3}\right)-\dfrac{-5}{27}\)

\(\dfrac{2}{9}.\left(\dfrac{-4}{3}+\dfrac{5}{3}\right)-\dfrac{-5}{27}\)

\(\dfrac{2}{9}.\dfrac{1}{3}-\dfrac{-5}{27}\)

\(\dfrac{2}{27}+\dfrac{5}{27}=\dfrac{7}{27}\)

phâng đó là bạn giữ nguyên số còn mũ thì cộng lại với nhau

\(4^6.4^8.4=4^{6+8+1}=4^{15}\)

c

\(a,\left(11.x-15^2\right):5=32\)

\(\left(11.x-225\right):5=32\)

\(11.x-225=32.5=160\)

\(11x=160+225=385\)

\(x=385:11\)

\(x=35\)

\(b,6.x\left[8^2-2\left(2^4-1\right)\right]=1020\)

\(6.x\left[64-2\left(16-1\right)\right]=1020\)

\(6x\left(64-2.15\right)=1020\)

\(6x\left(64-30\right)=1020\)

\(6x.34=1020\)

\(6x=1020:34=30\)

\(x=30:6\)

\(x=5\)

\(c,2^4.x-3.5.x=5^2.2^4\)

\(16.x-3.5.x=25.16\)

\(16.x-15.x=400\)

\(x=400\)

tính từ

5 + 4.3 = 5 + 12 = 17

a, ( 9,6 + 1,4) + 5,7 = 11 + 5,7 = 16,7

b, ( 7,5 - 5,5 ) - 7,3 = 2 - 7,3 = -5,3

c, (3,67 - 6,33) + 9,5 = -2,66 + 9,5 = 6,84