Answer:
Step-by-step explanation:
let X be the quantity of 100% acid
let Y be the quantity of 10% acid
X + Y = 90
Y = 90 - X
X(100) + Y(10) = 90(81)
X(100) + (90 - X)(10) = 90(81)
100X + 900 - 10X = 7290
90X = 6390
X = 71 L
Minus 2t both sides
-7=2t
times 3 both sides
-21=6t
6t=-21
Answer:

Step-by-step explanation:
Solve for 'x'.
To solve for 'x', isolate 'x'.
2.8a + 3.2x + 1 = 16.6
Subtract 1 from both sides. {Subtraction property of equality}
2.8a + 3.2x = 16.6 - 1
2.8a + 3.2x = 15.6
Subtract 2.8 a from both sides.
3.2x = 15.6 - 2.8a
Now, divide both sides by 3.2. {Division property of equality}

Answer:
(fog)(a) = a³ - 3a² + 4a - 2
= (a - 1)×(a² - 2a + 2)
Step-by-step explanation:
<u><em>Given</em></u> :
g(a) = a -1
f(a)= a³ +a
…………………………
(fog)(a) = f(g(a)))
= g(a)³ + g(a)
= (a - 1)³ + (a - 1)
= (a³ - 3a² + 3a - 1) + (a - 1)
= a³ - 3a² + 3a - 1 + a - 1
= a³ - 3a² + 3a + a - 1 - 1
= a³ - 3a² + 4a - 2
<u><em>Second method</em></u> :
(fog)(a) = f(g(a)))
= f(a - 1)
= (a - 1)³ + (a - 1)
= (a - 1)×[(a - 1)² + 1]
= (a - 1)×[a² - 2a + 1 + 1]
= (a - 1)×(a² - 2a + 2)