Q. f(x)=2x5+x4−18x3−17x2+20x+12 The function f is shown. If x−3 is a factor of f, what is the value of f(3)
Check Factor by Substitution: Since x−3 is a factor of f(x), we know that f(3) should equal 0. This is because if x−3 is a factor, then f(x) must be divisible by x−3, and the remainder when f(x) is divided by x−3 should be 0. We can verify this by substituting f(x)0 into the function f(x) and checking if the result is indeed 0.
Substitute x=3: Substitute x=3 into the function f(x):f(3)=2(3)5+(3)4−18(3)3−17(3)2+20(3)+12
Calculate f(3): Calculate the value of f(3):f(3)=2(243)+81−18(27)−17(9)+60+12
Continue Calculation: Continue the calculation: f(3)=486+81−486−153+60+12
Simplify Expression: Simplify the expression: f(3)=486−486+81−153+60+12
Combine Like Terms: Combine like terms: f(3)=0+81−153+60+12
Finish Calculation: Finish the calculation: f(3)=0
Confirm Factor: Since we have found that f(3)=0, this confirms that x−3 is indeed a factor of f(x), as expected. The value of f(3) is 0, which is consistent with the fact that x−3 is a factor of the polynomial f(x).