Question

a, [(6.x - 39) :3] .28 =5628

B,  5.(7.x- 45) = 2³ . 5² - 3².20

Giúp tớ nhanh vs aj

Answer 1

`#3107.101107`

a,

\([(6.x - 39) \div3] .28 =5628\)

`\Rightarrow (6x - 39) \div 3 = 5628 \div 28`

`\Rightarrow (6x - 39) \div 3 = 201`

`\Rightarrow 6x - 39 = 201 . 3`

`\Rightarrow 6x - 39 = 603`

`\Rightarrow 6x = 42`

`\Rightarrow x = 42 \div 6`

`\Rightarrow x = 7`

Vậy, `x = 7`

b,

`5(7x - 45) = 2^3 . 5^2 - 3^2 . 20`

`\Rightarrow 5(7x - 45) = 8.5.5 - 9.4.5`

`\Rightarrow 5(7x - 45) = 5.(8.5 - 9.4)`

`\Rightarrow 5(7x - 45) = 5.(40 - 36)`

`\Rightarrow 7x - 45 = 5.(40 - 36) \div 5`

`\Rightarrow 7x - 45 = 4`

`\Rightarrow 7x = 49`

`\Rightarrow x = 7`

Vậy, `x = 7.`