Please help me. The answer in the booklet says it’s R=3, but I need working out because I don’t get it.

Antonio made a scale model of a building. the model's scale is 1 inch to 235 feet and its height is 3.5 inches. what is the exact height of the actual building? enter your answer in the box.

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers