b) pt=> 2=60 vô lý => pt vô nghiệm
c) => 4(x^3-3x^2+3x-1)+15=47
=> 4x^3-12x^2+12x=36
=>

1)tìm x
a)3^(x+1)+3^x.5=216
=> 3^x .3 + 3^x .5 = 216
=> 8. 3^x = 216
=> 3^x = 27 = 3^3
=> x = 3
b)4^(x+2)-4^x=60
=> 16.4^x - 4^x = 60
=> 15.4^x = 60
=> 4^x = 4
=> x = 1
c)4.(x-1)^3+15=47
=> 4 (x - 1)^3 = 32
=> (x - 1)^3 = 8 = 2^3
=> x - 1 = 2
=> x = 3

a) 3^x+1+3^x. 5=216
3^x.3+3^x. 5=216
3^x(3+5)=216
3^x. 8=216
3^x=27
3^x=3^3
x=3
b) 4^x+2-4^x=60
4^x. 4^2-4^x=60
4^x(16-1)=60
4^x. 15=60
4^x=4
x=1
c) 4.(x-1)^3+15=47
4.(x-1)^3=32
(x-1)^3=8
(x-1)^3=2^3
x-1=2
x=3

)tìm x
a)3^(x+1)+3^x.5=216
=> 3^x .3 + 3^x .5 = 216
=> 8. 3^x = 216
=> 3^x = 27 = 3^3
=> x = 3
b)4^(x+2)-4^x=60
=> 16.4^x - 4^x = 60
=> 15.4^x = 60
=> 4^x = 4
=> x = 1
c)4.(x-1)^3+15=47
=> 4 (x - 1)^3 = 32
=> (x - 1)^3 = 8 = 2^3
=> x - 1 = 2
=> x = 3
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06/12/2020 16:44:20

+2đ tặng
a) 3^x+1+3^x. 5=216
3^x.3+3^x. 5=216
3^x(3+5)=216
3^x. 8=216
3^x=27
3^x=3^3
x=3
b) 4^x+2-4^x=60
4^x. 4^2-4^x=60
4^x(16-1)=60
4^x. 15=60
4^x=4
x=1
c) 4.(x-1)^3+15=47
4.(x-1)^3=32
(x-1)^3=8
(x-1)^3=2^3
x-1=2
x=2+1
x=3