If A-B > 0, then a > B. given A-B > 0, X-Y < 0, compare ax + by and BX + ay If A-B > 0, then a > B. given A-B > 0, X-Y < 0, compare AX = by and BX + ay Urgent excavation, to be handed in tomorrow

If A-B > 0, then a > B. given A-B > 0, X-Y < 0, compare ax + by and BX + ay If A-B > 0, then a > B. given A-B > 0, X-Y < 0, compare AX = by and BX + ay Urgent excavation, to be handed in tomorrow

ax+by -(bx+ay)
=ax+by -bx-ay
=(a-b)x-(a-b)y
=(a-b)(x-y)
Because A-B > 0, X-Y < 0
So (a-b) (X-Y) < 0
So ax + by < BX + ay