Formula query

[Dianah]

If a=5 b=3 and c=9, then:
5a + 3b - c = 23
I get this using the bidmas way by the following:
(5 x 5) + (3 x 3) - 9
25 + 9 - 9
34 - 9 = 23
However, I am told I am wrong and the answer is 25, meaning I should have done the subtraction before the addition (instead of 25 + 9 - 9 should be 25 + 0). Could someone please explain why bidmas doesn't apply to this formula?
Thanks

 

[tkhunny]

The difficulty has nothing to do with the Order in which Operations are performed.

[math]34 - 9 = 25 \ne 23[/math]

 

[Dianah]

The difficulty has nothing to do with the Order in which Operations are performed.

[math]34 - 9 = 25 \ne 23[/math]

Thanks, realised after I posted it but couldn't delete. Had a proper brain fog moment ?.

 

[tkhunny]

No worries. It's a good lesson for all.

 

[Steven G]

If you have ANY number which you add 9 to and then subtract 9 you end up with the starting number. This is even true if you replaced 9 with any number (positive or negative)