2 câu trả lời
`a)`
`4x^3 + 12 = 120`
`4x^3 = 120 - 12 `
`4x^3 = 108`
` x^3 = 108 : 4`
` x^3 =27`
` x^3 = 3^3`
`=> x = 3 `
`b)`
`3.2^x - 3= 45`
`⇒3.2^x =45+3`
`⇒3.2^x =48`
`⇒2x =48:3`
`⇒2x =16`
`=>2^4 =16`
`=>x=4`
a) 4x ³ + 12 = 120
4x ³ = 120 - 12
4x ³ = 108
x³ = 108 : 4
x³ = 27
x³ = 3³
=> x = 3
Vậy x = 3
b)$3.2^{x}$ - 3 = 45
$3.2^{x}$ = 45 +3
$3.2^{x}$ = 48
$2^{x}$ = 48 : 3
$2^{x}$ = 16
$2^{x}$ = 2$2^{4}$
=> x = 4
Vậy x = 4