Linear equations are often used to solve practical problems that have an
unknown quantity. We use a suitable pronumeral
to represent the unknown
quantity, translate the information given in the problem into an equation,
and then solve the equation using the skills acquired earlier in this
chapter.
Example 11
If a number is increased by 8, the result is 25. Find the number.
Solution:
Example 12
If a number is decreased by 4, the result is 29. Find the number.
Solution:
Example 13
If twice a number is equal to 68, find the number.
Solution:
Example 14
If a number is divided by 9, the result is 12. Find the number.
Solution:
Example 15
If three times a number decreased by 5 equals 82, find the number.
Solution:
Example 16
If one-half of a certain number is added to one-third of the same
number, the result is 10. Find the number.
Solution:
So, the number is 12.
Example 17
A rectangular paddock is twice as long as it is wide. If it has a
perimeter of 570 m, find its dimensions.
Solution:
Note:
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