What are some characteristics of a good math explanation?

X2 + y 2 = 36 x + y = 6 solve the system of equations.

Ab and bc are tangent to circle d. find x is ab = 3x + 8 and bc = 26. find x

Fatima plans to spend at least $15 and at most $20 dollars on sketch pads and pencils. if she buys 2 sketchpads, how many pemcils can she buy while staying in her price range? fatima can buy between and pencils. ? (type whole numbers. use ascending? order.)