(3) Prove the formula
(-7)+(-7)+...+(-7)= -7n
n of these
for n 1 by induction using these steps:
(a) Identify the proposition we want to prove and write "P(n) says ....".
(b) Check the basis step.
(c) Complete the inductive step as follows: write down what P(k) says, assume it's
true, and then use this to prove that P(k+1) must also be true.
(d) Write your conclusion: "So by mathematical induction P(n) is true for all n> 1".