Answer:
Step-by-step explanation:
[tex]1=1(3*1-1)/2\\1=2/2\\1=1\\[/tex] TRUE
[tex]1 + 4 +7 + ...+(3k -2) = k (3k - 1)/2\\[/tex]
[tex]1 + 4 +7 + ...+(3k -2)+ (3(k+1)-2) =k(3(k+1)-1)/2 \\[/tex]
We replace the first part of the equation with our value for n=k:
[tex]k (3k - 1)/2+(3(k+1)-2)=k(3(k+1)-1)/2 \\[/tex]
we develop both sides of the equation to verify equality:
[tex]3k^{2} /2-k/2+3k+1=(k+1)(3k+2)/2\\\\3k^{2} /2+5k/2+1=(3k^{2}+5k+2)/2\\\\3k^{2} /2+5k/2+1=3k^{2} /2+5k/2+1[/tex] TRUE