What operation should be performed first to simplify the following expression? Subtraction, multiplication, division, or addition 2-8 5.4+7

Is the number 128.439 a rational number

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4

Jack has a rectangular piece of land, the area of which is represented by a1 = 9.5l. his brother has a different rectangular piece of land, the area of which is represented by a2 = l(14 − l). let a represent the area in square meters and l represent the length in meters of the pieces of land. the two equations plotted on a graph meet at a point as shown in the image