Change of subject

Make "a" the subject. A=½(2a+b)r
Original post by Gideon Junior
Make "a" the subject. A=½(2a+b)r

The rule is that as long as you do the same thing to both sides of the equation then it will remain correct.

So we want to "reveal" the "a" by slowing removing anything currently on the right-hand side. What would happen if we multiplied both sides by 2? Or divided both sides by r? Can you continue from there?
Original post by Gideon Junior
Make "a" the subject. A=½(2a+b)r

A = 1/2(2a+b)r
2A = (2a+b)r
2A/r = 2a+b
2A/r -b = 2a
(2A/r - b)/2 = a
2A/2r - b/2 = a
FINAL ANSWER: a = A/r - b/2

I am not sure if this is correct but I have tried to work it out. If you do same thing on both sides, you will be able to get answer.
Steps what I did:

1.

I multiplied both sides by 2 which gave me 2A = (2a + b)r

2.

Then I divided both sides by r which gave me 2A/r = 2a + b

3.

Then I subtracted b from both sides which gave me 2A/r - b

4.

Then I divided both sides by 2 which gave me:

5.

for 2A/r = (2A/r)/2 which equals (2A/r) x 1/2 = 2A/2r = A/r

6.

for -b = -b/2

7.

By putting back in proper format you will get ur final answer

8.

FINAL solution: a = A/r -b/2

I hope it helps. If you need any more help let me know, I am happy to help. Please ask me if you found any of my working confusing.

Thanks