7. Tshering's height was 1.555 m when he was 12 years old and
1.7 m when he was 13 years old.
a) How much did he grow?
b) Explain how you could use
mental math to calculate part a).​

If the graphs of the linear equations in a system are parallel, what does that mean about the possible solution(s) of the system? a. there are infinitely many solutions. b. there is no solution. c. there is exactly one solution. d. the lines in a system cannot be parallel.

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Walking at a constant rate of 8 kilometers per hour, juan can cross a bridge in 6 minutes. what is the length of the bridge in meters?