Question

[Đăng Nguyên Nguyễn]

Tính hợp lí:
a) C = 75,284 x 15,137 x (9,5 - 4,75 x 2) + 231 x (7,25 + 2,75).
b) D = (1000 x 0,1 – 900 x 0,1 – 90 x 0,1)x(142 x 0,5 – 240 x 0,25).
c) E = 3,54 + 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25 

Answer 1

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a) \(C=75,284\cdot15,137\cdot\left(9,5-4,75\cdot2\right)+231\left(7,25+2,75\right)\)

\(C=75,284\cdot15,137\cdot\left(9,5-9,5\right)+231\cdot10\)

\(C=75,284\cdot15,137\cdot0+2310=2310\)

b) \(D=\left(1000\cdot0,1-900\cdot0,1-90\cdot0,1\right)\left(142\cdot0,5-240\cdot0,25\right)\)

\(D=\left[0,1\left(1000-900-90\right)\right]\left(142\cdot0,5-240\cdot0,5\cdot\frac{1}{2}\right)\)

\(D=\left(0,1\cdot10\right)\left(142\cdot0,5-140\cdot0,5\right)\)

\(D=0,5\left(142-140\right)\)

\(D=\frac{1}{2}\cdot2=1\)

c) \(E=3,54+73+0,23\cdot25+3,54\cdot27+0,17\cdot25\)

\(E=3,54\left(1+27\right)+73+25\left(0,23+0,17\right)\)

\(E=3,54\cdot28+73+25\cdot0,4\)

\(E=99,12+73+10\)

\(E=99,12+1+72+10\)

\(E=100,12+72+10=182,12\)