Gladis bulding a stage calcuate stea

Which matrix can be multiplied to the left of a vector matrix to get a new vector matrix ?

Aright triangle includes one angle that measures 30º. what is the measure of the third angle? a. 30º b. 90º c. 60º d. 130º

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .