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Please help me with this maths question!! :)

Please help with an explanation if that's ok:

If 17x - b = 4ax + 9x - 3a for all real values of x then,

A) a = -2, b = 6
B) a = -2, b = -6
C) a = 2, b = 6
D) a = 8, b = -24
Reply 1
Avatar for shamika
shamika
16
Original post by flyingpanda786
Please help with an explanation if that's ok:

If 17x - b = 4ax + 9x - 3a for all real values of x then,

A) a = -2, b = 6
B) a = -2, b = -6
C) a = 2, b = 6
D) a = 8, b = -24


There's an easy but long way to do this, which is to substitute each of the choices and see which works (I don't necessarily recommend that, however think about exam technique - if you're stuck on a multiple choice question like this in an exam, the easiest way to get the mark is to just work out which option works and move on).
Reply 2
Avatar for Notnek
Notnek
21
Original post by flyingpanda786
Please help with an explanation if that's ok:

If 17x - b = 4ax + 9x - 3a for all real values of x then,

A) a = -2, b = 6
B) a = -2, b = -6
C) a = 2, b = 6
D) a = 8, b = -24

Factorise:

17x - b = x(4a + 9) - 3a

Now try comparing coefficients of x.

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