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put this solution on YOUR website! If cx^2 - 74x - 7 = (11x + 1)(ax + b) , what is the value of c?
FOIL out (11x + 1)(ax + b)
11ax2 + 11bx + 1ax + b
Factor out x from the middle two terms:
11ax2 + (11b+a)x + b
Compare that with
cx2 - 74x - 7
Those must equal to each other, so we set the corresponding
terms equal to each other:
Setting first terms equal:
11ax2 = cx2
11a = c
Setting second terms equal:
(11b+a)x = -74x
11b+a = -74
Setting third terms equal:
b = -7
So we have the system of three equations:
Substitute b=-7 from the third equation into the second
equation:
11(-7)+a = -74
-77+a = -74
a = 3
Substitute in the first:
11a = c
11(3) = c
33 = c
Edwin