Updated: Sep 27, 2021
The equation y = 2x^2 - 5x - 4 graphs a parabola in the xy-plane? Which of the following is the y-coordinate of the y-intercept of the parabola?
A) -5
B) -4
C) 2
D) 5
Maps to Category 30 of the book.
There is a flashcard for this concept. It is accessible from the Resources page.
Answer posted on 09/19/2021: Correct answer choice is B.
In the standard form equation of a parabola the value of c is the y-coordinate of the y-intercept of the parabola.
Updated: Sep 12, 2021
The equation y = 2(x + 3)^2 - 4 graphs a parabola in the xy-plane? Which of the following is the vertex of the parabola?
A) (-3, -4)
B) (3, -4)
C) (6, -4)
D) (6, 4)
Maps to Category 31 of the book.
There is a flashcard for this concept. It is accessible from the Resources page.
Answer posted on 09/12/2021. Correct answer choice is A.
y = 2(x + 3)^2 - 4 is the vertex form equation of a parabola. From the vertex form equation, the x and y
coordinates of the vertex can be directly read.
In the given equation, the x-coordinate of the vertex is -3 and the y-coordinate of the vertex is 4. This is answer choice A.
Updated: Sep 6, 2021
What is the sum of the roots of the equation 2x^2 - 7x + 3 ?
Maps to Category 27 of the book.
Answer posted on 09/05/2021: Answer is 3.5 or 7/2.
The two factors are (2x-1) = 0 and (x-3) = 0.
Hence, the two roots are 1/2 or 0.5 and 3.
The sum of the roots is 1/2 + 3 = 3.5 or 7/2
