What is the surface area of the net?

Sundar used linear combination to solve the system of equations shown. he did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. what number did sundar multiply the second equation by? 2x+9y=41 3x+5y=36

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

What number line represents the solution set for the inequality -1/2 greater than or equal to 4