My whole class is stumped on it - including my teacher. The answer in the back of the book is aprox. 1.93.
You have to use logs to solve it obvs.
5^2 + 3^2x = 92
Can you like give me a walkthrough, or some hints or something? Going to go insane.
2007-10-12 14:11:16 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
ohh goodness, my apologies, WRONG question
5^x + 3^2x = 92
2007-10-12 14:16:48 · update #1
25+3^2x=92
sub 25
3^2x=67
ln both sides
ln3^2x=ln67
log rules allow you to move a power to a coefficient
2xln3=ln67
divide by ln3
2x=3.83
divide by 2
x=1.92
2007-10-12 14:21:00 · answer #1 · answered by Jasin P 2 · 0⤊ 0⤋
3^2x = 92 - 5^2 = 67
log(3^2x) = log67
2xlog3 = log67
x = log 67 / 2 log 3 = 1.914
2007-10-12 21:14:48 · answer #2 · answered by alphapower 2 · 0⤊ 0⤋
Rearrange the terms:
3^(2x) = 92 - 25 = 67
now take log of both sides:
log[3^2x)] = log 27
2x*log(3) = log(27)
x = log(27) / 2*log(3)
This gives your answer
2007-10-12 21:19:24 · answer #3 · answered by gp4rts 7 · 0⤊ 0⤋
25 + 9x = 92
2007-10-12 21:14:49 · answer #4 · answered by mishkin 5 · 0⤊ 0⤋
I assume the equation is:
5^2 + 3^(2x) = 92
25 + 3^(2x) = 92
3^(2x) = 67
2x*log(3) = log(67)
x =1/2*log(67)/log(3) = 1.913
2007-10-12 21:17:20 · answer #5 · answered by nyphdinmd 7 · 0⤊ 0⤋
You know, sometimes the answer in the back of the book is wrong = ) Happens quite often.
2007-10-12 21:24:24 · answer #6 · answered by Shicoco 3 · 0⤊ 0⤋
5x5=25
3x3=9
25+9=34
92-34=58
92/9=10.2
2007-10-12 21:16:03 · answer #7 · answered by Anonymous · 0⤊ 0⤋