Name the property of multiplication that is shown by the equation 4x*1=4x

Anyone know? will mark brainliest if correct!

Atriangle has an area of 72 square inches. if the base of the triangle has a length of 18 inches, what is the height of the triangle? use the formula for the area of a triangle: area = (base)(height) type a numerical answer in the space provided. do not include the units or spaces in your answer.

Solve the system of equations y= 3/2 - 1, -x+ y =-3