Ask your own question, for FREE!
Mathematics 10 Online
OpenStudy (dtan5457):

How do I solve this exponent problem?

OpenStudy (dtan5457):

\[3^x-2(3)^{1-x}=5\]

OpenStudy (dtan5457):

compute 3^(2x+1)

OpenStudy (faiqraees):

can you split 3^1-x in to two exponents?

jhonyy9 (jhonyy9):

great @FaiqRaees - this is the first step sure

OpenStudy (dtan5457):

can multiply 3^(x+1) on every side?

OpenStudy (faiqraees):

A^m * A^n = A^m+n

OpenStudy (dtan5457):

then I can get 3^(2x+1) on the left side

OpenStudy (faiqraees):

first its not 3^2x+1 its 2(3^1-x) and no. After this you can make the l.h.s a complete exponent of 3

OpenStudy (dtan5457):

ok if i split it i will get 3^1 x 3^-x

OpenStudy (faiqraees):

yes which will be \[3/3^x\]

OpenStudy (faiqraees):

now multiply the two with the fraction.

OpenStudy (dtan5457):

-6/3^x

OpenStudy (faiqraees):

and when you've done it make an equation y=3^x and then subsitute y in place of 3^x and then you've gotten a quadratic equation. Solve it find values of y and then use them to fund the values of x

OpenStudy (faiqraees):

find*

OpenStudy (dtan5457):

wait when i've done what? do i multiply the whole thing by 3^x now to remove the fraction?

OpenStudy (faiqraees):

yes

OpenStudy (dtan5457):

now I have 3^(2x)-6=3^(x)(5)

OpenStudy (dtan5457):

do i solve for x and put it back into 3^(2x+1)

OpenStudy (dtan5457):

or do i do that directly from the equation not sure

OpenStudy (dtan5457):

actually i see what you mean by quadratic equation i set 3^x=u then i get u^2-5u-6=0 i get 6,-1 do i set those 2 numbers to 3^x?

OpenStudy (faiqraees):

yes

OpenStudy (dtan5457):

so i solve for 3^x=6 and -1?

OpenStudy (faiqraees):

yes

OpenStudy (faiqraees):

btw you have to neglect -1 because no number when squared to any number results in a negative number.

OpenStudy (dtan5457):

how do i solve for x here again lol

OpenStudy (jdoe0001):

is \(\large\bf 3^x-2(3)^{1-x}=5\) it? just clarifying

OpenStudy (faiqraees):

apply logarithm

OpenStudy (dtan5457):

yes

OpenStudy (faiqraees):

should i walk you through the logarithm part or you know how to apply them

OpenStudy (dtan5457):

i remember the exponential form to log form, this becomes log3(6)=x but i actually forgot how to plug that into calculator

OpenStudy (jdoe0001):

use the log change of base rule, to make it either ln or base10

OpenStudy (dtan5457):

yeah i got it

OpenStudy (dtan5457):

its just log(6)/log(3)

OpenStudy (jdoe0001):

yeap

OpenStudy (dtan5457):

so answer we get 108

OpenStudy (jdoe0001):

hmmm log(3)/log(6) gives me something else =|

OpenStudy (faiqraees):

you have to use log 6 /log 3

OpenStudy (faiqraees):

and answer will be 1.630929

OpenStudy (dtan5457):

108 i meant for the problem

OpenStudy (jdoe0001):

ohhhh rats... yeah.. mistead there

OpenStudy (jdoe0001):

ohhh right

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!