What term should be added to create a perfect square trinomial?

x^2+18x

i think it's + 81 but i'm not positive.

An exam consists of 15 true-or-false questions. If a student guesses at every answer, what is the probability that he or she will answer exactly 9 questions correctly? (Round your answer to three decimal places.).

If y (x) = 3 (x+5) + -, what is a + 2) ?

Five friends went to a baseball game. Three of the friends each bought a ticket for x dollars and a soda for $6.00. The other two friends each bought only tickets. Write and simplify an expression that represents the amount of money spent.

The circumference of circle x in which a = 49pi in squared

A truck averages 17 miles per gallon. If gas is currently 2.38 per gallon, how much would be speed in gas the truck were to travel 630 miles?

The graph of f passes through (-10, 4) and is perpendicular to the line whose equation is x = - 4.

Jacob has 16 toy cars. 3/8 of the cars are red and the rest are blue. how many cars are blue

Sarah's Shipping and Ryan's Mail Services both ship packages. Sarah's trucks will only carry loads of 18 packages. In contrast, Ryan's trucks will only carry loads of 11 packages.

Which equation has a constant of proportionality equal to 15?

13, 967 round to the nearest 100