what is 'a'
2007-10-08 08:21:52 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
not sure but is it -3
2007-10-08 08:32:13 · update #1
if (x-2) is a factor, plugging in x-2=0, x=2 into the equation should give you a value of 0.
2^3+2^2a-4*2+12=0
4a=-12
a=-3
2007-10-08 13:30:32 · answer #1 · answered by Mugen is Strong 7 · 0⤊ 0⤋
If (x-2) is a factor of the polynomial then x-2=0, therefore x=2. Substitute x=2 into the polynomial.
2^3 + a.2^2 - 4.2 + 12 = 0
8 + 4a - 8 + 12 = 0
4a + 12 = 0
4a = -12
a = -3
the polynomial is therefore:
x^2 - 3x^2 - 4x +12
2007-10-09 06:38:28 · answer #2 · answered by john s 2 · 0⤊ 0⤋
Factor Theorem
2 = r
f(x) = x^3 + ax^2 - 4x + 12
f(r) = 0, if x-r is a factor.
f(2) = 8 + 4a - 8 + 12
0 = 4a + 12
4a = -12
a = -3
2007-10-08 08:35:54 · answer #3 · answered by UnknownD 6 · 0⤊ 0⤋
Use lon division getting a =3
2007-10-08 08:29:48 · answer #4 · answered by ironduke8159 7 · 0⤊ 0⤋