How many ways can 3 runners be selected for the Olympics from a field of 5 contestants?

Which expression is equivalent to 2x^2+7x+4?

Problem melissa is her dad build a walkway in their backyard. the walkway will be 54 feet long and 1.5 feet wide. the local hardware store sells tiles which are 1.5 by 1.5 feet and come in boxes of 12. how many boxes of tiles do they need?

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.