Find the vertex of this parabola y=-5x^2-10x-15
2 answers:
Answer:
vertex = (- 1, - 10 )
Step-by-step explanation:
given the equation of a parabola in standard form
y = ax² + bx + c : a ≠ 0
Then the x-coordinate of the vertex is
= -
y = - 5x² - 10x - 15 is in standard form
with a = - 5, b = - 10 and c = - 15, hence
= -
= - 1
substitute x = - 1 into the equation for y
y = - 5(- 1)² - 10(- 1) - 15 = - 5 + 10 - 15 = - 10
vertex = (- 1, - 10 )
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Answer:
y + 20 = 9(x + 2)
Step-by-step explanation:
The equation of a line in point- slope form is
y - b = m(x - a)
where m is the slope and (a, b) a point on the lie
Calculate m using the slope formula
m = (y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = (- 2, - 20) and (x₂, y₂ ) = (9, 79)
m = =
= 9
Using (a, b) = (- 2, - 20), then
y - (- 20) = 9(x - (- 2)), that is
y + 20 = 9(x + 2)