Someone help me please

Which letters from the table represent like terms? a and b b and c a and d b and d

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.

Matt had 5 library books. he checked out 1 additional book every week without retuening any books. whats the matching equation