x+2,x+3 are factors of 2x^3 +ax^2+7x-b find values of a,b
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x+2=0
x=-2
x+3=0
x=-3
2x³+ax²+7x-b=0
2(-2)³+a(-2)²+7(-2)-b=0
-16+4a-14-b=0
4a-b=30
2(-3)³+a(-3)²+7(-3)-b=0
-54+9a-21-b=0
9a-b=75→1
4a-b=30→2
subtract 1-2
9a-b=75
4a-b=30
5a=45
a=9
substitute in 1
9(9)-b=75
81-b=75
-b=-6
b=6
finally a=9,b=6
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