Question

solve the logarithmic equation: log4x + log4 (x+7)=log4(x+27)......H

Answer 1

I am struggling at this point, trying to pass a pre calculus class. I need all the help I can get so that I will not be out of school. Had algebra 1 and II but lost with pre calculus... HELP!!!!

Answer 2

is this the equation
log4x + log4(x+7) = log4(x+27) ?

Answer 3

yes it is

Answer 4

by law of logarithms
log4x + log4(x+7) = log16x(x+7)
so
log16x(x+7 = log4(x+27)
16x(x+7) = 4(x+27)
16x^2 + 112x = 4x + 108
16x^2 + 108x - 108 = 0
simplifying
4x^2 + 27x - 27 = 0
x = 0.884 or -7.634

Answer 5

I thank you very much....

Answer 6

ok

Answer 7

Hey one question.... on the question it should be log4 (x+7) = log4 (x+27).... is that the same as the problem you just worked.....

Answer 8

sorry... log 4 x+log4 (x+7)= log4 (x+27)

Answer 9

are you saying that these are logs to the BASE 4?

Answer 10

if so then my answer is wrong

Answer 11

sorry.. I went back and looked to make sure

Answer 12

so it s logs to base 4?

Answer 13

if so
then log4 x + log4 (x+7) = log4 x(x+7)
then

log4 x(x+7) = log4 (x+27)
and
x^2 + 7x = x + 27
x^2 - x - 20 = 0
x = 4 or -5

Answer 14

x = 4 since there is no real log of -5

Answer 15

Ok ..sorry for the confusion... I guess I am nervous about passing this class.. It has really been stressful for me and I can't thank you enough.....

Answer 16

no probs - practice these as much as you can - this will improve your confidence

Answer 17

I will definitely do that...have a great day!

Answer 18

ty