Which of the answer choices has matrix multiplication defined

Students buying lunch at rockwell elementary school yesterday chose either burritos or pizza. 185 students chose burritos and 252 chose pizza. 1. estimate the number of students who brought lunch by rounding each number to the nearest hundred. 2. estimate how many students bought lunch by rounding each number to the nearest ten. 3. find the total number of students who brought lunch. which of your estimates is closer to the actual total? explain. 4. draw a figure on a sheet of paper. estimate how many pennies will fit inside the figure. check your prediction using pennies.

3-12. write each answer with a reasonable number of figures. find the absolute uncertainty and percent relative uncertainty for each answer. (a) [12.41 (±0.09) + 4.16 (±0.01)] x 7.068 2 (±0.000 4) =? (b) [3.26 (±0.10) x 8.47 (±0.05)] - 0.18 (±0.06) =? (c) 6.843 (±0.008) x 104 + [2.09 (±0.04)- 1.63 (±0.01)] =?

What is the value of x in the diagram below?