SOLUTION: Solve:
a) log(base 7)(17y + 15) = 2 + log(base 7)(2y - 3)
b) lg(7x-3) + 2 lg 5 = 2 + lg(x + 3)
*Please answer as soon as possible :) :(
Algebra.Com
Question 395226: Solve:
a) log(base 7)(17y + 15) = 2 + log(base 7)(2y - 3)
b) lg(7x-3) + 2 lg 5 = 2 + lg(x + 3)
*Please answer as soon as possible :) :(
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
Solve:
a) log(base 7)(17y + 15) = 2 + log(base 7)(2y - 3)
b) lg(7x-3) + 2 lg 5 = 2 + lg(x + 3)
first problem:
log(base 7)(17y + 15) = 2 + log(base 7)(2y - 3)
log7(17y+15)=2+log7(2y-3)
log7(17y+15)-log7(2y-3)=2
using division rule for logs,
log7(17y+15)/(2y-3)=2
remembering that the base raised to the logarithm of the number is equal to the number. In this case, the base is 7, the logarithm is 2, and the number is (17y+15)/(2y-3)
7^2=(17y+15)/(2y-3)
49=(17y+15)/(2y-3)
98y-147=17y+15
98y-17y=147+15
81y=162
y=2
solving second problem
lg(7x-3) + 2 lg 5 = 2 + lg(x + 3)
using multiplication, power, and division rules of logarithms,
log(7x-3)+log 5^2-log(x+3)=2
log(7x-3)(5^2)/(x+3)=2
using the same rule as above problem
10^2=(7x-3)(5^2)/(x+3)
100=(7x-3)(25)/(x+3)
100=(175x-75)/(x+3)
100x+300=175x-75
75x=375
x=5
RELATED QUESTIONS
Thanks tutor for sloving this:
lg(2x)-3lg2={{{(1/2)lg(x-3)}}}
lg means log with base... (answered by scott8148)
simplify andexpress each of the following as a single log
i)lg (8/75)-2 lg(3/5)+4... (answered by MathLover1)
Log base 7 of 81 times log base 3 of 100 times lg base of... (answered by Alan3354)
Please solve lg(2x^2-5x+3)<=0,25lg81 +... (answered by ewatrrr)
lg(x-1)=2 (answered by mananth)
If {{{lg x^2y=a}}} and {{{lg (x/y) = b}}}, express {{{lg (y/x^2)}}} in terms of a and... (answered by josgarithmetic)
Solve the equation lg(3^x - 2 ^ (4-x )) = 2 + (1/3)lg 8 - (1/4)xlg16
This is how far I (answered by Alex.33)
Please solve... (answered by lwsshak3)
Solve for x:
A.) Log(base 3)4 + log(base 3)5 = log(base 3)(4x+5)
B.)log(base 7)6... (answered by algebrapro18)