Question

a) 2^x+3 + 2^x = 144

b) 7^x + 7^x+1 =392

c) 32 < 2^x <  2^2x-3 . 28^8-2x

d) 3^x + 3^x+3  =2268

e) 9^x+2 + 9^x - 9² . 82 =0

f) 8^x . 16^-2x  =4⁵

=> mIK ĐA CẦN GẮP CÓ BN NÀO CÓ THỂ GIÚP MIK DX KKO???

Answer 1

a)2^x+3+2^x=144

   2^x*2³+2^x=144

2^x * (2³+1)=144

2^x * 9 =144

2^x=144/9=16

2^x=16 =>x=4

b) 7^x+7^x+1=392

 7^x + 7^x * 7 =392

7^x * (1+7)=392

7^x * 8= 392

7^x= 392/8=49

7^x=49 => x=2

d)  3^x+3^x+3=2268

    3^x+ 3^x * 3³=2268

3^x *(1+3³)=2268

3^x*28=2268

3^x=2268/28 

3^x=81 =>x=4

e) 9^x+2+9^x-9²*82=0

 9^x*9²+9^x-9² *82=0

9^x*(9²+1)-9²*82=0

9^x*82-9²*82=0

82*(9^x-9²)=0

=>9^x-9²=0

9^x=0+9²=9²

=>x=2

f)8^x. 16^-2x=4⁵

2^3x. 2^{4 . -2x}=4⁵

 2^{3x+ 4 . -2x} =4⁵

2^3x-8x=4⁵

2^-5x =2¹⁰

=>-5x=10 =>x=-2

 

 

Answer 2

hi 

ai mua sim ko