Explanation: For questions 4-11, plug in the values of the variables into the equations. Ex no. 8: 7.8 + 3.5(w) where w=6.8. Plug 6.8 into the equation: 7.8 + 3.5(6.8) = 7.8 + 23.8 = 31.6 is the answer.
For questions 12-15, the order of operations is Please Excuse My Dear Aunt Sally: Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction. In other words, solve each equation according to the arrangement of the operations. Ex no. 15: y² - 10 ÷ 5 + x where x = 2.5 and y = 4. Plug these numbers into the equation: 4² - 10 ÷ 5 + 2.5. The order of operations says that parenthesis should be solved first. Since there are no parenthesis, we can skip this operation. The next operation is exponents. 4² has an exponent of 2, which means that we multiply 4 by itself 2 times to get 16 (4 x 4 = 16). We now have 16 - 10 ÷ 5 + 2.5. The next operation is multiplication. There is no multiplication in this equation, so we skip this operation. Next is division. We can divide -10 by 5 to get -2. We now have 16 - 2 + 2.5 (Do not change an addition sign unless you are dividing a negative number by a positive number). The next operation is addition. We can add -2 and 2.5 to get 0.5. Lastly, we can also add 16 by 0.5: 16 + 0.5 = 16.5 is the answer.
