Find the coordinate of the vertex of the following parabola algebraically. y=2x^2-28x+80

vertex = (7, - 18)

Step-by-step explanation:

given a parabola in standard form : ax² + bx + c : a ≠ 0

Then the x- coordinate of the vertex is

= -

y = 2x² - 28x + 80 is in standard form

with a = 2, b = -28 and c = 80, hence

= - = 7

substitute x = 7 into the equation for corresponding value of y

y = 2(7)² - 28(7) + 80 = 98 - 196 + 80 = - 18

vertex = (7, - 18)

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5