Maths Olympiad Prep

Library / /83 of 310

, 2023

Algebra Difficulty 1.4 Junior Find the answer Canada

If a(x+2)+b(x+2)=60a(x+2)+b(x+2)=60 and
a+b=12a+b=12, then xx is equal to

Pick one

Solution

The equation $a(x+2) + b(x+2) =
60hasacommonfactorof has a common factor of x+2$ on the left side.

Thus, we can re-write the equation as (a+b)(x+2)=60(a+b)(x+2) = 60.

When a+b=12a+b = 12, we obtain 12(x+2)=6012 \cdot (x+2) = 60 and so x+2=5x + 2 = 5 which gives x=3x = 3.

Want a route through all this instead of an archive? The track puts 2,444 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project.