Limits and Boundary and Func help

[mms6]

How close to 4 do we have to take x so that 3x + 2 is within a distance of (a) 0.1 and (b) 0.01 from 14?

http://i.imagehost.org/0222/Picture_1.png



a) Let k be any integer. Prove that if k^3 is even, then k is even.

b) Prove that 3√2 is irrational. Hint: Mimic the proof that √2 is irrational and apply the result from part (a).

c) Suppose two numbers a and b are irrational. Must the sum a + b be irrational? Justify your answer with an appropriate proof or counterexample


Thanks guys!

 

[LCKurtz]

These look like homework problems. Are they? What have you tried on them?