Explanation:
Find out the expressions for the number of sweets sue and tony have now .
To proof
As given
Sue has 18 sweets. tony has 18 sweets.sue gives tony x sweets
thus
sue sweets = 18 - x
Tony sweets = 18 + x
As given
Sue then eats 5 sweets. Tony then eats half of his sweets
sue sweets becomes = 18 -5 -x
= 13 - x
Tony sweets become= 18 + x /2
= 9+ x/2
hence proved.
Hence proved