9514 1404 393
Answer:
Step-by-step explanation:
Adding the same number to both sides of the equation is an acceptable move. The addition property of equality tells Grace that the value of the variable will remain unchanged by such a move.
Her new equation would be ...
2x +20 +10 = 15 +10
2x +30 = 25 . . . . the result of Grace's move
_____
<em>Additional comment</em>
There may be very good reasons why Grace would want to do that. If solving the equation is Grace's intent, that move would be counterproductive. For the purpose of solving the equation, it would be more productive to either subtract 20 from both sides, or divide both sides by 2. These steps would give, respectively, ...
2x = -5
x +10 = 7.5
There are a total of 31 fish in the tank. Therefore, the probability of it being a goldfish is 24/31 or about 77.4%, since there are 24 goldfish. The probability of it being an angel fish is 2/31 or about 6.45%, for the same reason as before.