Question

Solve 7.74x + 3 = 10.2

Answer 1

First, subtract 3 from both sides. Let me know what you get.

Answer 2

And then after what hero said, divide by 7.74

Answer 3

One step at a time @Veelution

Answer 4

7.74x= 7.20

Answer 5

Great. Now, as Veelution said, divide both sides by 7.74

Answer 6

oh wait ; i wrote the equation wrong : /
It's actually 7.7^4x+3=10.2

Answer 7

Wow, that greatly changes the outcome

Answer 8

Take logs of both sides, then

Answer 9

how in the would do i do that ?

Answer 10

i'm sorry , but i reall suck at math -_-

Answer 11

\(\log(7.7)^{4x}= \log(7.20)\)

Answer 12

i know the answer

Answer 13

@Snapbacklive, let me remind you again that giving answers is not helpful. Help students get to the answer, not give them.

Answer 14

i know but i didn't right

Answer 15

No, but you probably wanted to.

Answer 16

@Hero but i can't put the x into the equation in my calculator . so what do i do with it ? & i got the log of 7.20 .

Answer 17

x is nothing

Answer 18

You didn't have to necessarily use your calculator just yet. Usually, you want to wait until you have completely isolated x first.

Answer 19

it's just a sub

Answer 20

ahh , all of this is beyond confusing -_-

Answer 21

But anyway, here's the rule you're looking for @kianalauntra

\(\log(b)^a = a \log(b)\)

Answer 22

well it depends

Answer 23

i got that . . .

Answer 24

Okay, here's what you should have at this point:

\(4x \log(7.7) = \log(7.20)\)

Answer 25

Do you have an idea of what the next step might be?

Answer 26

do i get the logs of both ?

Answer 27

We should wait until the end before computing logs. For the next step, you want to divide both sides by \(\log(7.7)\). Remember we're trying to isolate x first.

Answer 28

Let me know what you get after dividing both sides by \(\log(7.7)\)

Answer 29

so it would be 4x=log(7.20)/log(7.7) ?

Answer 30

Yes, very good. Now, divide both sides by 4.

Answer 31

wait , how would i divide both sides by 4 if im already dividing the two logs ?

Answer 32

Multiply both sides by 1/4. Do it that way and let me know what you get.

Answer 33

x=log(7.7)/log(7.20)*0.25

Answer 34

i meant log(7.20)/log(7.7)

Answer 35

I would have written it like this just to be safe

\[\large x = \frac{\log(7.20)}{4 \log(7.7)}\]

Answer 36

Now, you can use your calculator to figure out an approximate value of x

Answer 37

omigod , thank you so much !

Answer 38

so x=.86/3.55 = .24 ?

Answer 39

Yes, correct, although anytime you have a decimal answer like that, you should probably write \(x \approx .24\) since it is a decimal approximation.

Answer 40

Great job :D

Answer 41

thank you <333 .