Đáp án + Giải thích các bước giải:
`1)` `85 - 2 × (x - 5) = 35.`
`⇒ 2 × (x - 5) = 85 - 35.`
`⇒ 2 × (x - 5) = 50.`
`⇒ x - 5 = 50 : 2.`
`⇒ x - 5 = 25.`
`⇒ x = 25 + 5.`
`⇒ x = 30.`
Vậy `x = 30.`
`2)` `45 + 6 × (x - 2) = 81.`
`⇒ 6 × (x - 2) = 81 - 45.`
`⇒ 6 × (x - 2) = 36.`
`⇒ x - 2 = 36 : 6.`
`⇒ x - 2 = 6.`
`⇒ x = 6 + 2.`
`⇒ x = 8.`
Vậy `x = 8.`
`3)` `15 + 3 × x = 32.33.`
`⇒ 15 + 3 × x = 1056.`
`⇒ 3 × x = 1056 - 15.`
`⇒ 3 × x = 1041.`
`⇒ x = 1041 : 3.`
`⇒ x = 347.`
Vậy `x = 347.`
`4)` `5 × x - 124 = 66 : 64.`
`⇒ 5 × x - 124 = 66/64.`
`⇒ 5 × x - 124 = 33/32.`
`⇒ 5 × x = 33/32 + 124.`
`⇒ 5 × x = 4001/32.`
`⇒ x = 4001/32 : 5.`
`⇒ x = 4001/160.`
Vậy `x = 4001/160.`
`5)` `2 × x - 158 = 90 - 23 × 32.`
`⇒ 2 × x - 158 = 90 - 736.`
`⇒ 2 × x - 158 = -646.`
`⇒ 2 × x = (-646) + 158.`
`⇒ 2 × x = (-488).`
`⇒ x = (-488) : 2.`
`⇒ x = (-244).`
Vậy `x = -244.`
$#hoangca159357#$
