Question

Tính:

1)142 -[50-(2³.5-2³.10)]

2)[(-18)+3].(-4)+(-72)

3)25-[49-(2².14-2².17)]

Answer 1

1: \(142-\left[50-\left(2^3\cdot5-2^3\cdot10\right)\right]\)

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

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

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

=142-90

=52

2: \(\left[-18+3\right]\cdot\left(-4\right)+\left(-72\right)\)

\(=\left(-15\right)\cdot\left(-4\right)+\left(-72\right)\)

\(=60-72=-12\)

3: \(25-\left[49-\left(2^2\cdot14-2^2\cdot17\right)\right]\)

\(=25-\left[49-2^2\left(14-17\right)\right]\)

\(=25-\left[49-4\cdot\left(-3\right)\right]\)

\(=25-\left[49+12\right]\)

=25-61

=-36