if x-1 and x+2 are factors of the polynomial f(x)=x^3+10x^2+ax+b. Find the values of a and b
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if x-1 and x+2 are factors then f(1)=0 and f(-2)= 0
when f(1)
0= 1+10+a+b
-11-a = b
when f(-2)
0= -8+40-2a+b
2a-32=b
substituting the first equation into the second
2a-32 = -11 -a
3a = 21
a = 7
and if a = 7 then
b = -11 -(7)
b = -18
when f(1)
0= 1+10+a+b
-11-a = b
when f(-2)
0= -8+40-2a+b
2a-32=b
substituting the first equation into the second
2a-32 = -11 -a
3a = 21
a = 7
and if a = 7 then
b = -11 -(7)
b = -18
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