87*23+19*93+70*87 295-(31-2^2*5)^2 0:ích=0 2 mũ ích :2^5=1

Đáp án:

`a) 9858.`

`b) 174.`

`c) 0.`

`d) 5.`

Giải thích các bước giải:

`a) 87 × 23 + 19 × 93 + 70 × 87.`

`= (87 × 23 + 70 × 87) + 19 × 93.`

`= 87 × (23 + 70) + 19 × 93.`

`= 87 × 93 + 19 × 93.`

`= (87 + 19) × 93.`

`= 106 × 93.`

`= 9858.`

`b) 295 – (31 – 2^2 × 5)^2.`

`= 295 – (31 – 4 × 5)^2.`

`= 295 – (31 – 20)^2.`

`= 295 – 11^2.`

`= 295 – 121.`

`= 174.`

`c) 0 ÷ x = 0.`

`⇒ x = 0.`

`d) 2^x ÷ 2^5 = 1.`

`⇒ 2^{x – 5} = 1.`

`⇒ 2^{x – 5} = 2^0.`

`⇒ x – 5 = 0.`

`⇒ x = 5.`