Rileyflipflop,

= 8

, since she can't buy half a CD, she's limited to no more than 8 CDs. If x = the cost of one CD, then x CDs cost $18x. Since we are limited to $153, our equation looks like... 18x < 153x < 8

Again, since we can't buy half a CD, your answer should actually be... x ≤ 8 since we can buy 8 CDs or fewer.
<span><u><em>The correct answer is: </em></u>
y=x.
<u><em>Explanation: </em></u>
<span>In order to find the inverse of a function, we first <u>switch x and y</u>; then we isolate y. When we do this, we are saying that x and y equal the same thing, or y=x. </span></span>
One example is the equation 2x+3x = 5x because the left hand side combines to form the right hand side. This equation is said to be an identity, which is always true for any real number you can think of. For example, if x = 3, then,
2x+3x = 5x
2*3+3*3 = 5*3 ... replace every x with 3
6 + 9 = 15
15 = 15
We end up with a true equation. This will happen regardless of what x value we pick. Therefore, it has infinitely many solutions.
Answer:
1.25 gallons of alcohol
Step-by-step explanation:
Let x represent the amount of alcohol to add to the mix. Then the total amount of alcohol in the mix is ...
0.15×20 + x = 0.20×(20 +x)
3 +x = 4 + 0.2x . . . . simplify
0.8x = 1 . . . . . . . . . . add -3-0.2x
x = 1/0.8 = 1.25 . . . . divide by 0.8
1.25 gallons of alcohol should be added to make 21.25 gallons of 20% alcohol.