Question

[nguyễn hữu bảo]

7) tính giá trị biểu thức

a) 2,3.(-6,4)+(-3,6).\(\left|-2,3\right|\)

b) \(\left|-\dfrac{2}{5}+\dfrac{1}{2}\right|\).(1\(\dfrac{3}{4}\)-0,75)

c) (0,75+\(\left|-\dfrac{1}{2}\right|\)-\(\dfrac{1}{3}\)):0,5+1\(\dfrac{3}{2}\)

d) \(\dfrac{1}{2}\)-\(\left|\left(-3\right).\dfrac{1}{6}\right|\)+\(\dfrac{5}{3}\)-\(\dfrac{9}{12}\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(2,3\cdot\left(-6,4\right)+\left(-3,6\right)\cdot\left|-2,3\right|\)

\(=2,3\left(-6,4-3,6\right)\)

\(=2,3\cdot\left(-10\right)=-23\)

b: \(\left|-\dfrac{2}{5}+\dfrac{1}{2}\right|\cdot\left(1\dfrac{3}{4}-0,75\right)\)

\(=\left|-\dfrac{4}{10}+\dfrac{5}{10}\right|\left(1+\dfrac{3}{4}-\dfrac{3}{4}\right)\)

\(=\dfrac{1}{10}\)

c: \(\left(0,75+\left|-\dfrac{1}{2}\right|-\dfrac{1}{3}\right):0,5+1\dfrac{3}{2}\)

\(=\left(\dfrac{3}{4}+\dfrac{1}{2}-\dfrac{1}{3}\right):\dfrac{1}{2}+\dfrac{5}{2}\)

\(=\left(\dfrac{9}{12}+\dfrac{6}{12}-\dfrac{4}{12}\right)\cdot2+\dfrac{5}{2}\)

\(=\dfrac{11}{12}\cdot2+\dfrac{5}{2}=\dfrac{11}{6}+\dfrac{5}{2}=\dfrac{11}{6}+\dfrac{15}{6}=\dfrac{26}{6}=\dfrac{13}{3}\)

d: \(\dfrac{1}{2}-\left|\left(-3\right)\cdot\dfrac{1}{6}\right|+\dfrac{5}{3}-\dfrac{9}{12}\)

\(=\dfrac{1}{2}-\left|-\dfrac{3}{6}\right|+\dfrac{20}{12}-\dfrac{9}{12}\)

\(=\dfrac{1}{2}-\dfrac{1}{2}+\dfrac{11}{12}=\dfrac{11}{12}\)