Answer : The equation could you use to find p is, 
Step-by-step explanation :
Let the cost of 1 pen be, 'x'
and the cost of 1 pencil is, 'p'
As we are given that total cost of 1 pen and 1 pencil is $2.10. The equation will be:
............(1)
And we have also given that the pen costs twice as much as a pencil. The equation will be:
............(2)
Now put the equation 2 in equation 1, we get:


Thus, the equation could you use to find p is, 
The correct answer is the 12 topping pizza one. Just turned it in and got 100 on it. good luck
Answer:
first one is simnple cross multiply and divide
12*7=4x
84=4x
x=21
2nd same process but more steps
7x=5(x+8)
7x=5x+40
7x-5x=40
2x=40
x=20
Step-by-step explanation: