Maths rearranging formula Q
make x the subject: ax = b - x
answer: x = b / a + 1
This is my working, where did I go wrong?
ax = b - x
ax + x = b
2x = b / a
x = b / a / 2
x = a / b
answer: x = b / a + 1
This is my working, where did I go wrong?
ax = b - x
ax + x = b
2x = b / a
x = b / a / 2
x = a / b
Original post by RedVelvet16
make x the subject: ax = b - x
answer: x = b / a + 1
This is my working, where did I go wrong?
ax = b - x
ax + x = b
2x = b / a
x = b / a / 2
x = a / b
answer: x = b / a + 1
This is my working, where did I go wrong?
ax = b - x
ax + x = b
2x = b / a
x = b / a / 2
x = a / b
In red's fine, but the line thereafter isn't.
Try taking out the x as separate factor, and hopefully all will be clear.
Original post by RedVelvet16
ax + x = b
2x = b / a
2x = b / a
It’s going from this line to the next, it manipulating algebra doesn’t work like that
Can you factorise ax+x ?Original post by laurawatt
It’s going from this line to the next, it manipulating algebra doesn’t work like that Can you factorise ax+x ?
Can you factorise ax+x ?is it x(a+1)?
Original post by ghostwalker
In red's fine, but the line thereafter isn't.
Try taking out the x as separate factor, and hopefully all will be clear.
Try taking out the x as separate factor, and hopefully all will be clear.
ax + x = b
a + x = b / x
x + x = b / a ?
No. Like you said, x(a + 1) = b
Then that will become...
Then that will become...
Original post by sweetescobar
No. Like you said, x(a + 1) = b
Then that will become...
Then that will become...
x(a + 1) = b
x = b / a + 1
ahh that makes more sense now thank you!!
Original post by RedVelvet16
is it x(a+1)?
Yes, so we have x(a+1) = b
Can you see the last step?
Original post by RedVelvet16
is it x(a+1)?
yes
Original post by laurawatt
It’s going from this line to the next, it manipulating algebra doesn’t work like that Can you factorise ax+x ?
Can you factorise ax+x ?yes, it makes sense now; thank you!!
Thanks everyone -- I understand now!
Would I always have to factorise?
Would I always have to factorise?
Always, whenever you are trying to rearrange for a variable there is two of, get them on the same side, and factorise
Original post by sweetescobar
Always, whenever you are trying to rearrange for a variable there is two of, get them on the same side, and factorise
thanks so much! that really helps with the other questions in my textbook!
No problem.
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