Make y the Subject of Formula

Rearrange equation to make y the subject. See how to deal with a square root

[@sanjan8593]

Hi ! Very useful video, just wanted to check if one would lose marks if they forgot to simplify it into 4(x^2....)?

[@MathsWithJay]

No....it's fine so long as y is the subject

[@2infinitybeyond655]

It was easy to put y = 1 to check our solution

[@2infinitybeyond655]

I wanted to write y = 1 it was my mistake

[@MathsWithJay]

You could have put x = 1 to check it too...as in your initial question!

[@MathsWithJay]

The really important point here, is to understand that you can check this sort of answer numerically....it doesn't matter whether you choose a starting value for x or y.

[@2infinitybeyond655]

okay
if we put x = 1 then we get y = 136 from the solution
we get the same result from the original question.

[@MathsWithJay]

Excellent!

[@eldin5788]

dont make sense how on earth u got 10x thats mad

[@MathsWithJay]

(x + 5)^2 = (x + 5)(x + 5) = x^2 + 5x + 5x + 25

[@purrr9153]

@@MathsWithJay yeah so how did you get 10x?

[@MathsWithJay]

5x + 5x

[@ProfMark]

x = -5/2,

[@MathsWithJay]

YES! Well done!