How do you solve (1/7)^(y-3)=343(17)y3=343?

2 Answers
Nov 8, 2016

Please see the explanation for steps leading to the answer: y =0y=0

Explanation:

Given:

(1/7)^(y - 3) = 343(17)y3=343

Take the natural logarithm on both sides:

ln((1/7)^(y - 3)) = ln(343)ln((17)y3)=ln(343)

Use the property of logarithms log_b(a^c) = (c)log_b(a)logb(ac)=(c)logb(a) on the left side:

(y - 3)ln(1/7) = ln(343)(y3)ln(17)=ln(343)

Divide both sides by ln(1/7)ln(17):

y - 3 = ln(343)/ln(1/7)y3=ln(343)ln(17)

Use the property of logarithms log_b(1/a) = -log_b(a)logb(1a)=logb(a) on the ln(1/7)ln(17):

y - 3 = ln(343)/-ln(7)y3=ln(343)ln(7)

Add 3 to both sides:

y = 3 - ln(343)/ln(7)y=3ln(343)ln(7)

y = 0y=0

Nov 8, 2016

y=0y=0

Explanation:

(1/7)^(y-3)=343(17)y3=343

now 7^3=34373=343

& (1/7)^-1=7(17)1=7

:.(1/7)^(y-3)=7^(3-y)

7^(y-3)=7^3=343

=>y-3=0

:.y=0