Answer:
x = 7
Step-by-step explanation:
12x - 66 + 15 = 3x +12
12x - 51 = 3x + 12
9x = 63
x = 7
Answer:: The family budget to make the one-way trip should be $70. Since, they need 20 gallons for driving out of state to her grandmother's house
Step-by-step explanation:

Taking 4 out from first two terms, we will get

Now we divide the coefficient of x by 2 and add and subtract the square of the result, we will get

Distributing 4

Cancelling 9

And that's the required standard form.
In normal circumstances, you would multiply the amount of boxes by 3, and the amount of pounds by 4. So you do the same here:
3b + 4p
Mr McKay spent 3b + 4b in total