Simultaneous equations cannot be solved

Answer 1

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.

This is copied from my other worked examples. I do not really understand your question. If you have a simultaneous equation that you can't solve. Post it up and i will help.

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Good answer, but spoiled by the last-but-one paragraph. Simultaneous linear equations with two variables can have no solutions (if the corresponding graphs are distinct parallel lines) or infinitely many solutions (if they are, in effect, the same line). And then, there are always simultaneous non-linear equations. Two quadratics, for example, can have 0, 1, 2 or infinitely many solutions.