To see if a pair of ratios is proportional... you need to compute for its cross products. If the cross products are equal then they are proportional.
a/b = c/d where ad = bc
a) 4/9 = 16/45 ⇒ 4*45 = 9*16 ⇒ 180 = 144 NOT PROPORTIONAL
b) 5/12 = 25/144 ⇒ 5*144 = 12*25 ⇒ 720 = 300 NOT PROPORTIONAL
c) 12/18 = 18/27 ⇒ 12*27 = 18*18 ⇒ 324 = 324 PROPORTIONAL
d)15/20 = 7/10 ⇒ 15*10 = 20*7 ⇒ 150 = 140 NOT PROPORTIONAL
Answer:
D
Step-by-step explanation:
Given
(x - 5)³ = (x - 5)(x - 5)(x - 5)
Expand (x - 5)(x - 5) using FOIL then multiply the result by (x - 5)
(x - 5)(x - 5)
= x² - 5x - 5x + 25 = x² - 10x + 25, then
(x - 5)(x² - 10x + 25)
= x(x² - 10x + 25) - 5(x² - 10x + 25)
= x³ - 10x² + 25x - 5x² + 50x - 125 ← collect like terms
= x³ - 15x² + 75x - 125 → D
To find the inverse, interchange the variables and solve for y.
f^−1(x)=−25+5x/2
Answer:
20
Step-by-step explanation:
6/x + 2x²
6/3 + 2(3)²
2 + 2(9)
2 + 18
20
