Which choice is appropriate simplified form and restriction for the variable (x+3)(x+7)/3x+21

a) 3/x+7 (x ≠ -7)

b) x+7/3 (x ≠ -7)

c) x+3/3 (x ≠ -7)

d) 3/x+3 (x ≠ -3)

and explain the answer too!

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

How many ordered pairs of positive integers satisfy xy=32?

3x = 729 solve for x plz . it's urgent. will mark