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Can u solve these 2 equations without calculator?
3.9^(x+1) = 27^(x-1)
2.4^(x+1) = 16^(2x)
^ means : to the power of.
5 Answers
- DOVELv 69 years agoFavourite answer
9^(x+1) = 27^(x-1)
(3^2)^(x+1)= (3^3)^(x-1)
3^2(x+1)= 3^3(x-1)
2(x+1)=3(x-1)
2x+2=3x-3
x=5
4^(x+1) = 16^(2x)
(2^2)^(x+1)=(2^4)^(2x)
2^2(x+1)= 2^(8x)
2(x+1)=8x
2x+2=8x
6x=2
x=1/3
- ComoLv 79 years ago
This presentation is rather misleading.
Will take a guess at :-
Qu1
3.9^(x + 1) = 27^(x - 1)
3.3^(2x + 2) = 3^(3x - 1)
3^(2x + 3) = 3^(3x - 1)
2x + 3 = 3x - 1
4 = x
Qu 2
2.4^(x+1) = 16^(2x)
2 [ 2^(2x + 2) ] = 2^(8x)
2^(2x + 3) = 2^(8x)
2x + 3 = 8x
3 = 6x
x = 1/2
Will have another guess as to how questions are meant to read:-
Qu 1
[ 9^(x + 1) ] = 27^(x - 1)
[ 3^(2x + 2) ] = 3^(3x - 3)
2x + 2 = 3x - 3
5 = x
Qu 2
4^(x + 1) = 16^(2x)
4^(x + 1) = 4^(4x)
x + 1 = 4x
1 = 3x
x = 1/3
PS
Out of interest could you clarify how questions were meant to be read?
- RameshwarLv 79 years ago
(3)9^(x+1) = 27^(x-1)
or 3^2( x+1) = 3^3( x-1)
or 2(x+ 1) = 3 ( x- 1 )
or 2x + 2 = 3x -3
or x= 5 ans
proof ------------------------------------
9^(5+1) = 9^6 = (3^2)^6 = 3^12
27^(5-1) =27^4 = (3^3)4 = 3^12
(2) 4^(x+1) = 16^(2x)
or 4^(x+1) = 4^2*2x= 4^4x
or x+ 1 = 4x
or x= 1/3 ans
proof-------------
4^(1/3+ 1) =4^4/3
16^( 2*1/3) = 4^2*2/3= 4^4/3
- Anonymous9 years ago
3.9^(x+1) = 27^(x-1) OR 3^(2x + 3) = 3^(3x -- 3) whence 3x -- 3 = 2x + 3 OR x = 6 ANSWER
2.4^(x+1) = 16^(2x) OR 2^(2x + 3) = 2^(8x) whence 8x = 2x + 3 OR 6x = 3 OR x = 1/2 ANSWER