Answer:
candles = $400
matches = $20
Step-by-step explanation:
Let cost of candles = $c
Let cost of matches = $m
c = 20 m (20 times m)
c + m = 420
20m + m = 420
21 m = 420
m = 20
c = 20 (20) = 400
Answer:
) See annex
b) See annex
x = 0,5 ft
y = 2 ft and
V = 2 ft³
Step-by-step explanation: See annex
c) V = y*y*x
d-1) y = 3 - 2x
d-2) V = (3-2x)* ( 3-2x)* x ⇒ V = (3-2x)²*x
V(x) =( 9 + 4x² - 12x )*x ⇒ V(x) = 9x + 4x³ - 12x²
Taking derivatives
V¨(x) = 9 + 12x² - 24x
V¨(x) = 0 ⇒ 12x² -24x +9 = 0 ⇒ 4x² - 8x + 3 = 0
Solving for x (second degree equation)
x =[ -b ± √b²- 4ac ] / 2a
we get x₁ = 1,5 and x₂ = 0,5
We look at y = 3 - 2x and see that the value x₂ is the only valid root
then
x = 0,5 ft
y = 2 ft and
V = 0,5*2*2
V = 2 ft³
Answer: -18
<u>Explanation:</u>
Average rate of change is slope: 
. Need to find the y-coordinates:
g(x) = -x² - 4x
g(6) = -(6)² - 4(6)
= -36 - 24
= -60
⇒ (6, -60)
g(8) = -(8)² - 4(8)
= -64 - 32
= -96
⇒ (8, -96)
m = 
= 
= -18
