-Simplify the expression. 2(-y + 9) + 8y

Agroup of students want to create a garden. they do not know the exact measurements but they propose using a variable to represent the length and width of the garden. the length of the garden is 10 feet longer than double the width. use a single variable to write algebraic expressions for both the length and width of the garden. write an algebraic expression for the area of the garden. use mathematical terms to describe this expression.

The given diagram shows the parts of a right triangle with an altitude to the hypotenuse. using the two given  measures, find the other four.

The measurement of one angle of a right triangle is 42° what is the measurement of the third angle? (there is no picture)