Download Grade 8 Math Notes Dec

Solving Word Problems Algebraically
This is probably the most difficult stuff you’ll have to do. There is no special routine to follow
to guarantee you’ll get them correct every time. I will give you some steps to follow that will
make it a bit easier
We will use the following example:
Two consecutive whole numbers add to 43. What are the numbers?
Step 1: Read and re-read the question like 10 times! Read it slowly. Figure out what is
given and what you need to find.
Given: Sum = 43
Find: two consecutive whole numbers (consecutive means one after the other)
Step 2: Identify the variables(make the unknown = to x). Usually developed by what you are
being asked to find (two consecutive whole numbers).
Let x = the first number
Let (x + 1) = the second number
Step 3: Make an equation. Usually developed by what you are given.
Sum = 43
First # + Second # = 43
x + (x + 1) = 43
Step 4: Solve for the unknown variable
x + (x + 1) = 43
2x + 1 = 43
2x = 42
x = 21
Step 5: Write a concluding sentence
the two numbers are 21 and 22 (x + 1 = 22)
Try These
1. Five more than twice a number is 93
Step 1: What is given? What do you need to
find?
Step 2: Identify the Variable(s)
x = a number
Given: Total = 93
Find: a number (times 2 + 5)
Step 3 and 4: Make an Equation and Solve for the variable
2x + 5 = 93
2x = 88
x = 44
Step 5: Write a concluding statement answering the question.
 the number is 44
2. The length of a rectangular garden is 6m more than twice its width. The perimeter of
the garden is 36m. What are the dimensions of the garden?
Step 1: What is given? What do you need to
find?
Given: P = 36. I also know that P = 2(l + w)
Step 2: Identify the Variable(s)
w = width
l = 6 more than twice the width
= 2w + 6 (given to us)
Find: length and width
Step 3 and 4: Make an Equation and Solve for the variable
P = 2(l + w)
36 = 2(2w + 6 + w)
36 = 2(3w + 6)
36 = 6w + 12
24 = 6w
4=w
Step 5: Write a concluding statement answering the question.
 the width is 4m and the length is 14m (2w + 6 = 2(4) + 6 = 14).