How can you do a simultaneous equation in maths? - Answers

Simultaneous Equations are very helpful because it can help u solve problems in real life. There are 2 ways to approach a simultaneous equation, Substitution and elimination method. As a good practice it is always good to practice your substitution method first. I wont go too advance for now but consider this question; Find two numbers whose sum is 21 and difference is 9. This question requires 2 equation to solve; thus it is call simultaneous equation. Solve: Let x be a number, and Let y be another number. x + y = 21 equation 1 x - y = 9 equation 2 Rearrange equation 2 to make equation 3(Equation 3 is just to sub into the other eqs) x = 9 + y equation 3 Sub equation 3 into 1 (9 + y) + y = 21 9 + 2y = 21 2y = 12 y = 6 First solution! Sub y = 6 into equation 2 x - 6 = 9 x = 15 Second Solution! Therefore, the numbers are 15 and 6. In a simultaneous equation (with 2 variable) there will always be 2 answers. Good luck and hope this help.