A weightlifter uses a total of 12 plates to add 260 pounds to a bar. He uses 45-pound plates and 10-pond plates. Write and solve a system of equations to find the number x of 45-pond and the number y of 10-ponds plates he uses.

45 pound plate = 4

10 pound plate = 8

Step-by-step explanation:

x = 45 pound plate

y = 10 pound plate

x + y = 12 - - - (1)

45x + 10y = 260 - - (2)

x = 12 - y

45(12 - y) + 10y = 260

540 - 45y + 10y = 260

540 - 35y = 260

-35y = 260 - 540

-35y = - 280

y = 280 / 35

y = 8

x = 12 - y

x = 12 - 8

x = 4

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or