At football practice, the coach ends practice with sprint drills. Starting at the endzone, players sprint to the 10-yard line and back, the 25-yard line and back, and finally the 50-yard line and back. How much ground in yards is covered if all 11 players complete the drill.

the answer is a if my teacher taught me correct

step-by-step explanation:

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -