Pls help :(

There are 15 plates and each plate is either 7 or 12 inches diameter. which systems of equations do you use to find the number of 7 inch plates, x and 12 inch plates, y

The ratios of boys to girls on a soccer league is 2: 5. if there are 28 boys, how many girls are playing soccer? extra points! will mark as brainiest asap

Solve for x in the equation x2 - 12x + 36 = 90. x= 6+3x/10 x=6+2/7 x= 12+3/22 x = 12+3/10