`a)2^x-15=17`
`=>2^x=15+17`
`=>2^x=32`
`=>2^x=2^5`
`=>x=5`
`b)(7x-11)^3=2^5*5^2+200`
`=>(7x-11)^3=32*25+200`
`=>(7x-11)^3=1000`
`=>(7x-11)^3=10^3`
`=>7x-11=10`
`=>7x=10+11`
`=>x=21/7=3`
`c)x^3=4^2*2^2`
`=>x^3=16*4`
`=>x^3=64`
`=>x^3=4^3`
`=>x=4`
`d)x^2021=x^10`
`=>x^2021-x^10=0`
`=>x^10*(x^2011-1)=0`
`=>x^10=0` hoặc `x^2011-1=0`
`=>x=0` hoặc `x^2011=1^2011`
`=>x=0` hoặc `x=1`
a) 2ˣ - 15 = 17
2ˣ = 17 + 15
2ˣ = 32
2ˣ = 2⁵
x = 5 (nhận)
Vậy x = 5
b) (7x - 11)³ = 2⁵.5² + 200
(7x - 11)³ = 32.25 + 200
(7x - 11)³ = 800 + 200
(7x - 11)³ = 1000
(7x - 11)³ = 10³
7x - 11 = 10
7x = 10 + 11
7x = 21
x = 21 : 7
x = 3 (nhận)
Vậy x = 3
c) x³ = 4².2²
x³ = 4².4
x³ = 4³
x = 4 (nhận)
Vậy x = 4
d) x²⁰²¹ = x¹⁰
x²⁰²¹ - x¹⁰ = 0
x¹⁰.(x²⁰¹¹ - 1) = 0
x¹⁰ = 0 hoặc x²⁰¹¹ - 1 = 0
*) x¹⁰ = 0
x = 0 (nhận)
*) x²⁰¹¹ - 1 = 0
x²⁰¹¹ = 0 + 1
x²⁰¹¹ = 1
x²⁰¹¹ = 1²⁰¹¹
x = 1 (nhận)
Vậy x = 0; x = 1
