Question

1. tính

a) 2[3 . 5/2 - 2(7 - 5)] + 3

b) 3 {120 + [55 - (11 - 3 . 2)2]} + 2/3

Answer 1

\(a,=2.\left[\dfrac{15}{2}-2.2\right]+3\\ =2.\left(\dfrac{15}{2}-4\right)+3\\ =2.\left(\dfrac{15}{2}-\dfrac{8}{2}\right)+3\\ =2.\dfrac{7}{2}+3\\ =7+3=10\\ ------------------\\ b,=3.\left\{120+\left[55-\left(11-6\right).2\right]\right\}+\dfrac{2}{3}\\ =3.\left[120+\left(55-10\right)\right]+\dfrac{2}{3}\\ =3.\left(120+45\right)+\dfrac{2}{3}\\ =3.165+\dfrac{2}{3}\\ =495+\dfrac{2}{3}=\dfrac{14873}{3}\)