How do you solve the equation (5x/6)(5x/2) = 5^{16}

Consider the function represented by the equation 1/2 j + 1/4 k equals 3 which shows the equation written in function notation with j as the independent variable

Rena is building a 1: 180 scale model of a real castle. her model has a rectangular base that is 3 feet wide and 4 feet long what is the area of the base of the actual castle in square feet

What is the value of x in the equation 1.5x+4-3=4.5(x-2)?