Question #3624b

2 Answers
Jun 13, 2017

#x=log_(25/32)500#

Explanation:

#5^(2x-3)-2^(5x+2)=0#
#5^(2x-3)=2^(5x+2)#
Taking the natural logarithm of both sides,
#ln(5^(2x-3))=ln(2^(5x+2))#
#(2x-3)ln5=(5x+2)ln2#
#(2ln5)x-3ln5=(5ln2)x+2ln2#
#(2ln5)x-(5ln2)x=3ln5+2ln2#
#[ln(5^2)-ln(2^5)]x=ln(5^3)+ln(2^2)#
#x=ln(5^3*2^2)/ln(5^2/2^5)#
#x=ln(125*4)/ln(25/32)#
#x=log_(25/32)500#

Jun 13, 2017

Given: #5^(2x-3)-2^(5x+2)= 0#

Move the second term to the right:

#5^(2x-3)=2^(5x+2)#

Use the base 5 logarithm on both sides:

#log_5(5^(2x-3))=log_5(2^(5x+2))#

Use the identity #log_b(a^c) = (c)log_b(a)# on both sides:

#(2x-3)log_5(5)=(5x+2)log_5(2)#

Use the property #log_b(b) = 1# on the left:

#2x-3=(5x+2)log_5(2)#

Use the distributive property on the right:

#2x-3=5log_5(2)x+2log_5(2)#

Subtract #5log_5(2)x# from both sides:

#(2-5log_5(2))x-3=2log_5(2)#

Add 3 to both sides:

#(2-5log_5(2))x=3+2log_5(2)#

Divide both sides by the coefficient of x:

#x=(3+2log_5(2))/(2-5log_5(2))#

Convert to base e by using the conversion formula #log_5(x)= ln(x)/ln(5)#:

#x=(3+2ln(2)/ln(5))/(2-5ln(2)/ln(5))#

Multiply by 1 in the form of #ln(5)/ln(5)#:

#x=(3ln(5)+2ln(2))/(2ln(5)-5ln(2))#