How to solve 3y^2+6y=12

How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor are shown below? I calculated that the area of the shape is 10.95m squared, but the answer in the book (183 tiles) is different then the answer I got. Where did I go wrong?

If Harriet rolls a number cube 39 times, how many times can she expect to roll a 3 or a 4?

Sinker is a weight used by fishermen. A fisherman uses a sinker in the shape of a sphere with radius 0.750.75 cm. The sinker is made of lead, which has density 11.34gmcm311.34gmcm3. What is the mass of the sinker?

The losing team in a baseball game scored 2 runs. Which inequality represents the number of runs, r, that the winning team could have scored? A. R?2 B. R>2 C. R<2 D. R=2

A factory made about 75,000 robots last year. The actual number of robots made was rounded to the nearest thousand.

Becky is using the expression 2z + 3 to represent the number of chairs in her classroom. There are twice as many chairs as tables, and there are three extra chairs in the back. What does z represent?

The last line of a proof represents the given information. the argument. the conclusion. the assumptions.

The question is solve the standard algorithm

Which is the decimal equivalent of one half?

Charlie saves $21.45 each month for 6 months. in the seventh month, he saves $10.60. how much money will charlie saved after seven months