Sometimes we are given an equation with brackets in.
Usually it is best to multiply out the brackets first.
Solve this equation: | |||
5 ( x - 3 ) | = | 35 | |
Start by multiplying out the brackets: | |||
5x - 15 | = | 35 | |
Now add 15 to both sides: | |||
5x | = | 50 | |
Finally divide by 5 on both sides: | |||
x | = | 10 |
Gilda thinks of a number and adds 7 to it. She then multiplies her answer by 4 and gets 64. What was her original number?
Start by working out the equation to solve. Let's call Gilda's original number x. |
4 ( x + 7 ) | = | 64 | |
Start by multiplying out the brackets: | |||
4x + 28 | = | 64 | |
Now subtract 28 from both sides: | |||
4x | = | 36 | |
Finally divide by 4 on both sides: | |||
x | = | 9 | |
So Gilda's original number was 9. |
Practice QuestionsWork out the answer to each of these questions then click on the button marked to see whether you are correct.
(a) Solve the equation: 7(x+3) = 49
(b) James thinks of a number. He subtracts 2 and then multiplies by 5 and gets 45. What was his number?
(c) Look at the rectangle below:
ExercisesWork out the answers to the questions below and fill in the boxes. Click on the button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on to see the answer.
Produced by A.J. Reynolds February 2004 |