Question

Cho A = \(\dfrac{6,62^2+5,4.3,38+1,22.3,38}{33,1.7,1+33,1.12,9}\)

a) Rút gọn A

b) Tìm B bt \(15\) % của B bằng A

Answer 1

Gọi \(C=6,62^2+5,4\cdot3,38+1,22\cdot3,38\\ D=33,1\cdot7,1+33,1\cdot12,9\)

\(C=6,62^2+5,4\cdot3,38+1,22\cdot3,38\\ =6,62\cdot6,62+3,38\cdot\left(5,4+1,22\right)\\ =6,62\cdot6,62+3,38+6,62\\ =6,62\cdot\left(6,62+3,38\right)\\ =6,62\cdot10=66,2\)

\(D=33,1\cdot7,1+33,1\cdot12,9\\ =33,1\cdot\left(7,1+12,9\right)\\ =33,1\cdot20\\ =662\)

\(A=\dfrac{C}{D}=\dfrac{66,2}{662}=\dfrac{662}{6620}=\dfrac{1}{10}\)

\(B=A:15\%=\dfrac{1}{10}\cdot\dfrac{100}{15}=\dfrac{10}{15}\)

Vậy \(A=\dfrac{1}{10}\\ B=\dfrac{10}{15}\)