The point r is halfway between the integers on the number line below and represents the number

I’m stuck on this i don’t understand.

This is so harddd! solve. 1 + 1 = solve 4 + 4 = solve 3 x 3

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36