Question

$\begin{gathered}y=x^2-2x-15 \\ y=2x+6\end{gathered}$
Which of the following could be the y-coordinate of a point of intersection of the graphs of the two equations above in the xy-plane?
A) -3
B) 5
C) 7
D) 20​

Answer 1

Answer:

Hi there! :)

Answer:

• D) 20

Step-by-step explanation:

Given functions:

• y = x^2 - 2x - 15
• y = 2x + 6

Intersection is when the function have common points

• x^2 - 2x - 15 = 2x + 6
• x^2 - 4x - 21 = 0
• x^2 - 4x + 4 - 25 =0
• (x - 2)^2 = 25
• x - 2 = 5 ⇒ x = 7
• x - 2 = -5 ⇒ x = -3

y-coordinates are:

• y = 2*7 + 6 = 20
• y = -3*7 + 6 = -15

Correct answer option is D) 20.

Best of luck for your exam! :-D

Answer 2

Answer:

Sorry, i don't know...!