equations & brackets.. you are now going to solve more complex equations by combining together...
Post on 24-Dec-2015
215 Views
Preview:
TRANSCRIPT
Equations & Brackets.
You are now going to solve more complex equations by combining together two ideas that you have seen already . Try the following questions to make sure you are ready:
Idea 1:
Solve the equation
3x – 6 = 18
Solution :
x = 8
Idea 2 :
Multiply out the bracket
3 ( 2x – 4 )
Solution :
6x – 12
We are now going to combine these two ideas together to solve the equations on the following pages.
Solving Equations.Example 1 .
Solve the equation :
2 ( x + 4 ) = 14
Solution.
2( x + 4 ) = 14 Multiply out the bracket first.
2x + 8 = 14 Subtract 8 from both sides.
2x = 6 Divide both sides by 2 .
x = 3 Hint: check the solution by substituting x = 3 into the original equation.
Example 2 .
Solve Solve the equation :
2 ( 3x + 2 ) = 28
Solution:
2( 3x + 2 ) = 28
What should you do first ?
Multiply out the bracket.
6x + 4 = 28 What comes next ?
Subtract 4 from each side.6x = 24
What comes next ?
Divide each side by 6.
x = 4
Check your answer by putting x = 4 back into the bracket.
Example 3 .
Solve the equation :
5( x – 3 ) = 20
Solution.
5 ( x – 3 ) = 20 What does 5 times –3 equal.
-155x – 15 = 20
What must you do to both sides?
Add 15
5x = 35
x = 7
Check the answer.
What Goes In The Box 1 ?Solve the following equations:
(1) 2 ( x + 4 ) = 14
(2) 3 ( 2x + 5 ) = 27
(3) 5 ( 2x + 6 ) = 100
(4) 4 ( 3x – 5 ) = 40
(5) 7 ( 2 x – 6 ) = 28
(6) 3 ( 4 + 2x ) = 30
x = 3
x = 2
x = 7
x = 5
x = 5
x = 3
top related