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India
Class VII

One and two step equations II

Lesson

One step equations

Here we are looking at solving one step equations, where we only need to do one thing in order to find the answer.

The aim is to work out the unknown value, such as $x$x. To do this, we look at both sides of the equation, and apply what we know from addition, subtraction, multiplication and division to work out the answer.

When we are trying to solve for $x$x, we need to make $x$x the subject of the equation. This means that we need to rearrange the equation so that $x$x is on its own.

The most important thing to remember is that we need to keep both sides balanced. As we learnt from Balancing, what we do to one side, we must do the other. 

 

Examples

Question 1

Solve: $-10x=-50$10x=50

Question 2

Solve: $\frac{x}{8}=6$x8=6

 

 

Extra hint

To double check the answer is correct, take the answer you found for x and insert it back into the original equation. If the two sides equal, you know for sure you have the right answer.

 

Two step equations

Finding the unknown value in two step equations follows the exact same method as for one step equations. Here, you will need to do two steps in order to find the answer. This will most likely involve a combination of addition, subtraction, multiplication or division. 

Just as in one step equations, the aim is to make the unknown value the subject of the equation. To do so, it is important to remember the Order of Operations. However, when solving equations, we use the order of operations in reverse.

Examples

Question 4

Solve the following equation: $-x-7=7$x7=7

Question 5

Solve the following equation:

$3\left(5-x\right)=0$3(5x)=0

 

Outcomes

7.A.AE.5

Simple linear equations in one variable (in contextual problems) with two operations (avoid complicated coefficients)

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