You can
put this solution on YOUR website! if a-b=5 and ab=-1, what is the numerical
value of
(2a+3b-2ab)-(a+4b+ab)-(3ab+2b-2a)
Remove the parentheses:
2a+3b-2ab-a-4b-ab-3ab-2b+2a
Put like terms together:
2a-a+2a + 3b-4b-2b - 2ab-ab-3ab
Combine like terms:
3a - 3b -6ab
Factor 3 out of first two terms:
3(a - b) - 6ab
Substitute (5) for (a - b) and (-1) for ab
3(5) - 6(-1)
15 + 6
21
That's the easy way.
(The hard way would be to first solve the system
a - b = 5
ab = -1
and then substitute.)
Edwin
