Answer:
see explanation
Step-by-step explanation:
Given
23x + xy - y + 3y + 5 - 20x + 6xy ← collect like terms
= (23x - 20x) + (xy + 6xy) + (- y + 3y) + 5
= 3x + 7xy + 2y + 5
He combined the coefficients of the x- term incorrectly
He combined the coefficients of the y- term incorrectly
He missed out the constant term ( + 5)
