Answer:
True
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k) = (- 4, - 9), thus
y = a(x + 4)² - 9
To find a substitute the coordinates of the zero (- 7, 0) into the equation.
0 = a(- 7 + 4)² - 9, that is
0 = 9a - 9 ( add 9 to both sides )
9a = 9 ( divide both sides by 9 )
a = 1, thus
y = (x + 4)² - 9 ← expand factor using FOIL
y = x² + 8x + 16 - 9
y = x² + 8x + 7
Answer:
46656
Step-by-step explanation:
<h3>Given</h3>
Two positive numbers x and y such that xy = 192
<h3>Find</h3>
The values that minimize x + 3y
<h3>Solution</h3>
y = 192/x . . . . . solve for y
f(x) = x + 3y
f(x) = x + 3(192/x) . . . . . the function we want to minimize
We can find the x that minimizes of f(x) by setting the derivative of f(x) to zero.
... f'(x) = 1 - 576/x² = 0
... 576 = x² . . . . . . . . . . . . multiply by x², add 576
... √576 = x = 24 . . . . . . . take the square root
... y = 192/24 = 8 . . . . . . . find the value of y using the above equation for y
The first number is 24.
The second number is 8.
