Whats the differnece between parallel and perpendicular lines?

Use the function f(x) is graphed below. the graph of the function to find, f(6). -2 -1 1 2

Eric has challenged himself to walk 24,000 steps in 4 days. if eric walks the same number of steps each day, which function represents the number of steps eric still needs to walk to reach his goal with respect to the number of days since he started his challenge? a. y = 8,000x − 24,000 b. y = -8,000x + 24,000 c. y = 6,000x − 24,000 d. y = -6,000x + 24,000

X2 + y 2 = 36 x + y = 6 solve the system of equations.