Answer: time to reach maximum height = 605
Step-by-step explanation:
The expression that relates height with time is
M(d)=-0.123x^2+148.83x-21.07
Where time = x
d = height
The expression is a quadratic equation. If height of the object is plotted against time, the resulting graph is a parabola whose vertex is equal to the maximum height attained by the object. The time, x corresponding to the vertex is the time for it to reach maximum height.
To find x,
x = -b/2a
Where a= 0.123
b = 148.83
x = - 148.83 / -2 × -0.123
x = -148.83 / -0.246
= 605
Substituting x = 605 in the equation,
M(d)=-0.123x^2+148.83x-21.07
d = -0.123 × 605^2 + 148.83×605
= - 45021.075+ 90042.15
= 45020.4
Approximately 45000 feet
The first step I would take is
.. Multiply both sides of the equation by 1/4.
_____
You could start by adding 16 to both sides of the equation, to make the left side the square (2x +4)^2.
Answer:
10.4
Step-by-step explanation:
Let the number be x
Sum of x and -3.2 : x + (-3.2) = x - 3.2
1/4 times the sum of a number and −3.2 = (1/4) * (x - 3.2)

x = 10.4