State whether the equations provided are true or false and why

Answer:
a) true
b) false
c) false
Step-by-step explanation:
remember: if a negative exponent is in the numerator, move the expression to the denominator and make the exponent positive and if a negative exponent is in the denominator, move the expression to the numerator and make the exponent positive
a explanation- 7a x 1/b^3 = 7a/b^3
b explanation- z^-5/12 = 1/12z^5
c explanation- 1/-7x^-1 = -7x
... please give brainliest if you can :)) ...