Tham khảo tài liệu 'math test english 2', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ------------------------------ ACT MATH TEST PRACTICE --------------------------------------- Linear Equations An equation is solved by finding a number that is equal to an unknown variable. Simple Rules for Working with Equations 1. The equal sign separates an equation into two sides. 2. Whenever an operation is performed on one side the same operation must be performed on the other side. 3. Your first goal is to get all of the variables on one side and all of the numbers on the other. 4. The final step often will be to divide each side by the coefficient leaving the variable equal to a number. Cross-Multiplying You can solve an equation that sets one fraction equal to another by cross-multiplication. Crossmultiplication involves setting the products of opposite pairs of terms equal. Example x x 1210 becomes 12x 6 x 6 10 12x 6x 60 -6x -6x 6x 60 6 6 Thus x 10 Checking Equations To check an equation substitute the number equal to the variable in the original equation. Example To check the equation from the previous page substitute the number 10 for the variable x. x _ x 10 6 12 10 10 10 6 12 10 20 6 12 Simplify the fraction on the right by dividing the numerator and denominator by 2. -106 6 Because this statement is true you know the answer x 10 is correct. 149 ACT MATH TEST PRACTICE Special Tips for Checking Equations 1. If time permits be sure to check all equations. 2. Be careful to answer the question that is being asked. Sometimes this involves solving for a variable and than performing an operation. Example If the question asks for the value of x - 2 and you find x 2 the answer is not 2 but 2 - 2. Thus the answer is 0. Charts Tables and Graphs The ACT Math Test will assess your ability to analyze graphs and tables. It is important to read each graph or table very carefully before reading the question. This will help you to process the information that is presented. It is extremely important to read all of the information presented paying special attention to .
