There are 12 students in your math class. 4 of them are wearing glass. 4 times the x amount of students are not wearing glass. Find the number x.
First, you will have to set up an equation. So take the total amount of students in the class, 12. 12 equals the number of students with and without glass. Replace the word with numbers. So 12= 4x+4. Now you are going to get rid of the 4 with glass. To get rid of 4 you have to subtract it. When you do something on one side you have to do it to the other, so you will have to subtract it from 12. You should get 8. Now you have 8=4x, you have to make x by itself. So, you have to divide by 4 on both sides. The answer should x = 2.
There are 50 students in your math class. 10 of them are wearing a red shirt. 20 of them are wearing a blue shirt. 5 of them are wearing yellow. 25 of them are wearing black. What is the percent of students wearing black shirts?
Think as if it was a fraction. The numerator is the number of students wearing black. The denominator is the number of the total students. So it would be 25/50. However, this number can be reduce. Divide the numerator and the denominator by 25. The answer should be 1/2 of 50%.
Remember the word F.O.I.L.. This word should make it useful to help you solve the problem. F stands for first. So take the first number in both parentheses, the 3x and the 4x. You will multiply them together to make 12x^2. (Do not forget the x squared). Next part is the O. This means Outside. So take the 3x and the 3 to multiply them together. You should get 9x. Then I means Inside. So take 4 and 4x to multiply them together. You should get 16x. Next letter is L, which means last. You will have to take the last two numbers in the parentheses and multiply them together, so the 4 and the 3. You should get the number 12 as your answer. Now, take all the numbers and put them together. You should get 12x^2 + 9x+16x+ 12. However, that is not the final answer you still need to combine like numbers. So you have to add the 9x and the 16x, which equals 25x. The final answer should be 12x^2 +25x+ 12.