Question

make a the subject of the formula s=a/4+8u
will medal

Answer 1

@UsukiDoll

Answer 2

s = a/4 + 8u

Subtract both sides by 8u.

s - 8u = a/4

Multiply both sides by 4.

a = 4(s - 8u)

Answer 3

are we solving for a in this question?

Answer 4

O.O

Answer 5

I just want clarification before I go further

Answer 6

@Sophhh786 is this question about solving for a ? as in having a by itself?

Answer 7

yes

Answer 8

alright so given the equation
\[s= \frac{a}{4}+8u\]
is this your equation?

Answer 9

yes

Answer 10

alright so.. we need to get rid of the fraction. Therefore multiply 4 throughout the equation. Can you do that?

Answer 11

yes 4s =a+8u

Answer 12

close.
the 4s and the a is right but for the 8u
it should be 4(8u) = 32u

Answer 13

why?

Answer 14

because we are multiplying 4 throughout the equation. every term is going to be multiplied by 4

Answer 15

\[(4)s= \frac{a(4)}{4}+8u (4)\]

Answer 16

so it is like linear equations

Answer 17

yeah

Answer 18

so now we have
\[4s=a+32u\]
so we just need one more step. What do we need to do to get a by itself?

Answer 19

divide 4 y both sides

Answer 20

by

Answer 21

not exactly.. we need a by itself and we have this equation. it's like get all the terms that's NOT a to the left
so I need to subtract both sides by 32u

Answer 22

i still dont understand why we need to multiply everything by 4 in the equation u should just multiply the 4 in the fraction and s ?

Answer 23

we multiplied 4 throughout the equation at the beginning to get rid of the fraction

Answer 24

there's more than one way to solve this... first is what I and undeadknight did earlier which was to multiply 4 throughout the equation to get rid of the fraction that was attached to a. then subtract 32u on both sides. it will look something like this
\[4s=a+32u \]
\[4s-32u=a+32u-32u \]
\[4s-32u=a \]

Answer 25

so let's do an alternative version where we don't multiply 4 throughout the equation first.

Answer 26

ok

Answer 27

\[s= \frac{a}{4}+8u \]
is the original equation. and we need a by itself. so I have to shift all terms (except a because we need it by itself to the right)
therefore subtract 8u on both sides

Answer 28

\[s-8u= \frac{a}{4}\]
so we have a by itself... but now we have to divide each term by 1/4

Answer 29

im gonna stick with the first method you told me im gonna go through it step by step now if I have any difficulties in understanding i will give you a shout yeah? Thanks though :)

Answer 30

ok. :)
yeah I prefer what @undeadknight26 did... for dividing 1/4 all over the equation.. we have to flip that second fraction (it will become 4/1 and then you have to use multiplication) because there's no such thing as dividing fractions.

Answer 31

yeh actually @undeadknight26 version makes sense to me

Answer 32

and fewer steps too :)

Answer 33

the only thing i dont get is why has he inserted brackets has he factorized in the last stage or something

Answer 34

oh ... in that step there was a 4 in common so he took it out

Answer 35

a=4(s-8u)
distributing the 4 gives us
a=4s-32u
now we split up the number 32

a=4s-(4)(8)u
there is a 4 on each term so we yank it out
a=4(s-8u)

Answer 36

could you write it like this though a=4s-32 would that be appropriate for the final answer?

Answer 37

yeah

Answer 38

ok thanks @undeadknight26 and @UsukiDoll

Answer 39

you're welcome :)