Understanding how to solve linear equations

Question 1

Fill in the missing number

5 + ____ = 9

Answer 1

4

Why? Because 9 - 5 = 4

Question 2

Fill in the missing number

7 + ____ = 9

Answer 2

2

Why? Because 9 - 7 = 2

Question 3

Fill in the missing number

7 + ____ = 15

Answer 3

8

Why? Because 15 - 7 = 8

Question 4

Fill in the missing number

4 * ____ = 20

Answer 4

5

Why? Because 20/4 = 5

Question 5

Fill in the missing number

10 * ____ = 20

Answer 5

2

Why? Because 20/10 = 2

Question 6

What do we mean ‘solve a linear equation’?

x + 5 = 7

Answer 6

We need to find the value of the variable, in this case x

What is the value of x such that both sides of the equation balance

Question 7

Does this look similar?

Solve for

x + 5 = 7

Fill in the black

___ + 5 = 7

Answer 7

Yes, we are finding a value such the left hand side of the equation and right hand side are the same

Question 8

Solve for

x + 5 = 7

or Fill in the black

___ + 5 = 7

Answer 8

x = 7 - 5

= 2

We do the reverse operation, hence we subtract 5

Question 9

Solve for

x - 5 = 7

or Fill in the black

___ - 5 = 7

Answer 9

x = 7 + 5

= 12

We do the reverse operation, hence we add 5

Question 10

Solve for

2x = 14

or Fill in the black

2 * ___ = 14

Answer 10

x = 14/2

= 7

We do the reverse operation, hence we divide by 2

Question 11

Solve for

x/2 = 14

or Fill in the black

____ /2 = 14

Answer 11

x = 14 * 2

= 28

We do the reverse operation, hence we multiply by 2