Get the answers you need at Westonci.ca, where our expert community is always ready to help with accurate information. Get immediate and reliable solutions to your questions from a community of experienced experts on our Q&A platform. Connect with a community of professionals ready to help you find accurate solutions to your questions quickly and efficiently.
Sagot :
To verify that a value is a root of a function we use the following setup
F(x) = 0 and replace x by the value in this case 3 and -i.
Let's begin with x=3
[tex]\begin{gathered} f(x)\text{ = }x^3+3x^2+x+3 \\ f(3)\text{ = }3^3+3\cdot3^2+3+3 \\ f(3)\text{ = 60} \end{gathered}[/tex][tex]\begin{gathered} f(x)\text{ = }x^5+9x^4+28x^3+36x^2+27x+27 \\ f(3)\text{ = 3}^5\text{+9}\cdot3^4\text{{}+28}\cdot3^3\text{+36}\cdot\text{3}^2\text{+27}\cdot3\text{+27} \\ f(3)\text{ = 2160} \end{gathered}[/tex][tex]\begin{gathered} f(x)\text{ = }x^5-9x^4+28x^3-36x^2+27x-27 \\ f(3)\text{ = 3}^5-\text{9}\cdot3^4\text{{}+28}\cdot3^3-\text{36}\cdot\text{3}^2\text{+27}\cdot3-\text{27} \\ f(3)\text{ = 0} \end{gathered}[/tex][tex]\begin{gathered} f(x)\text{ = }x^3+3x^2+x+3 \\ f(3)\text{ = }3^3-3\cdot3^2+3-3 \\ f(3)\text{ = 0} \end{gathered}[/tex]Only options C and D pass the first filter.
Let's apply x=-i to those options
[tex]f(-i)\text{ = }(-i\text{\rparen}^5\text{ - 9}\cdot\left(-i\right)^4\text{ + 28}\cdot\text{\lparen-i\rparen}^3\text{ - 36}\cdot(-i)^2+27\cdot(-i)-27[/tex][tex]\begin{gathered} f(-i)\text{ = }-i\text{ - 9 + 28 i - 36}-27i-27 \\ f(-i)\text{ = 0} \end{gathered}[/tex][tex]f(-i)\text{ = \lparen-i\rparen}^3-3\left(-i\right)^2+(-i)-3[/tex][tex]\begin{gathered} f(-i)\text{ = i+ }3-i-3 \\ f(-i)\text{ = 0} \end{gathered}[/tex]both of the accomplish the equality f(x)=0
So to finish we replace the point to check which functions pass
Replacing f(1) = -16
[tex]\begin{gathered} \left(1\right)^5-9\cdot\left(1\right)^4+28\cdot(1)^3-36^{\cdot}(1)^2+27\cdot(1)-27 \\ f(1)\text{ = -16} \end{gathered}[/tex]This is equals to -16
[tex]\begin{gathered} \text{ f\lparen1\rparen= 1- }3+1-3 \\ f(1)=-4 \end{gathered}[/tex]So the answer is option C
We hope our answers were useful. Return anytime for more information and answers to any other questions you have. Thank you for visiting. Our goal is to provide the most accurate answers for all your informational needs. Come back soon. Westonci.ca is your trusted source for answers. Visit us again to find more information on diverse topics.