Finding the vertex of a quadratic and the product of two complex numbers

[drop]

Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :)

PART A

11) Find the vertex of f(x) = -2x^2 - 8x + 3 algebraically.

My Answer: (-2,0)

12) Multiply and simplify: (6 - 5i) (4 + 3i)

My Answer: 39 - 2i

 

[anemone]

Re: Please check my answers - 6

Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :)

PART A

11) Find the vertex of f(x) = -2x^2 - 8x + 3 algebraically.

My Answer: (-2,0)

I get $(-2, 11)$. Now can you help me by explaining to us how did you arrive at $(-2, 0)$ as the vertex of the function of f of x?

12) Multiply and simplify: (6 - 5i) (4 + 3i)

My Answer: 39 - 2i

Correct.:)

 

[drop]

Re: Please check my answers - 6

x = -b/(2a)

x = -(-8)/2(-2)

x = 8/-4 = -2

I think I forgot to substitute -2 for x to find out y, thanks for pointing that out! (I was thinking of x intercepts) After solving for y, I got (-2,11) Thank you

 

[anemone]

Re: Please check my answers - 6

Yes...and as you can see, $f(-2)=-2(-2)^2-8(-2)+3=11$.

 

[CellCoree]

Good job on finding the vertex of the given quadratic function! Your answer for the vertex is correct, which means that the x-coordinate of the vertex is -2 and the y-coordinate is 0. To check your answer, you can also graph the function and see if the vertex matches your answer.

For the product of two complex numbers, your answer is also correct. To multiply complex numbers, you can use the FOIL method (First, Outer, Inner, Last) or distribute the terms. Make sure to combine like terms and simplify the resulting expression.

Overall, it seems like you have a good understanding of these concepts. Keep up the good work! If you have any further questions or need help with other concepts, don't hesitate to ask. Keep exploring and learning, as science is all about curiosity and discovery. Good luck!