Sorry it's a bit messy. but I hope you understand and it will help
Answer:
+ 8x³ + 12x² - 16x + 4
Step-by-step explanation:
Given
[(x² + 4x) - 2 ]² ← simplify contents of bracket
= (x² + 4x - 2)² = (x² + 4x - 2)(x² + 4x - 2)
Each term in the second factor is multiplied by each term in the first factor, that is
x²(x² + 4x - 2) + 4x(x² + 4x - 2) - 2(x² + 4x - 2) ← distribute parenthesis
=
+ 4x³ - 2x² + 4x³ + 16x² - 8x - 2x² - 8x + 4 ← collect like terms
=
+ 8x³ + 12x² - 16x + 4
Answer:
(y - 25) = - 0.25(x - 20)
Step-by-step explanation:
Given that :
Height of candle after burning for 20 minutes = 25 cm
Height after burning for 1 hr (60 minutes) = 10 cm
Height (y) in cm of candle x minutes after being lit:
Using the equation :
(y - y1) = m(x - x1)
m = (change in y / change in x)
Change in height within 60 minutes :
Height at 20 minutes = 25cm
Height after an hour = 10
Change in height per hour = (25 - 10) = 15cm
Hence, m = change in height per minute
15cm / 60 = 0.25cm ( - 0.25) (decrease in height)
y1 = 25 ; x1 = 20
(y - y1) = m(x - x1)
(y - 25) = - 0.25(x - 20)