**Solving System of Equations by Substitution Worksheet :**

Worksheet given in this section will be much useful for the students who would like to practice problems on solving system of equations by substitution.

Before look at the worksheet, if you would like to learn how to solve system of equations by substitution,

**Problem 1 : **

Solve for x and y :

x + y = 5

2x + 3y = 5

**Problem 2 : **

Solve for x and y :

2x + 5y = 12

4x - y = 2

**Problem 3 : **

Solve for x and y :

x + y - 4 = 0

2x - 3y - 18 = 0

**Problem 4 : **

Solve for x and y :

3x + 5y = - 2

2x - y = 3

**Problem 5 : **

If there is a total of 9 bicycles and unicycles and there are 13 wheels in total, find the number of bicycles and unicycles.

**Problem 1 : **

Solve for x and y :

x + y = 5

2x + 3y = 5

**Solution : **

x + y = 5 -----(1)

2x + 3y = 5 -----(2)

**Step 1 :**

Solve (1) for y.

x + y = 5

Subtract x from each side.

y = 5 - x -----(3)

**Step 2 : **

Substitute (5 - x) for y into (2).

(2)-----> 2x + 3(5 - x) = 5

2x + 15 - 3x = 5

15 - x = 5

Subtract 15 from each side.

-x = -10

Multiply each side by (-1).

x = 10

**Step 3 :**

Substitute 10 for x into (3).

(3)-----> y = 5 - 10

y = -5

Therefore, the solution is

(x, y) = (10, -5)

**Problem 2 : **

Solve for x and y :

2x + 5y = 12

4x - y = 2

**Solution : **

2x + 5y = 12 -----(1)

4x - y = 2 -----(2)

**Step 1 :**

Solve (2) for y.

4x - y = 2

Subtract 4x from each side.

-y = 2 - 4x

Multiply each side by (-1).

y = 4x - 2 -----(3)

**Step 2 : **

Substitute (4x - 2) for y into (1).

(2)-----> 2x + 5(4x - 2) = 12

2x + 20x - 10 = 12

22x - 10 = 12

Add 10 to each side.

22x = 22

Divide each side by 22.

x = 1

**Step 3 :**

Substitute 1 for x into (3).

(3)-----> y = 4(1) - 2

y = 4 - 2

y = 2

Therefore, the solution is

(x, y) = (1, 2)

**Problem 3 : **

Solve for x and y :

x + y - 4 = 0

2x - 3y - 18 = 0

**Solution : **

x + y - 4 = 0 -----(1)

2x - 3y - 18 = 0 -----(2)

**Step 1 :**

Solve (1) for x.

x + y - 4 = 0

Add 4 to each side.

x + y = 4

Subtract y from each side.

x = 4 - y -----(3)

**Step 2 : **

Substitute (4 - y) for x into (2).

(2)-----> 2(4 - y) - 3y - 18 = 0

8 - 2y - 3y - 18 = 0

-5y - 10 = 0

Add 10 to each side.

-5y = 10

Divide each side by -5.

y = -2

**Step 3 :**

Substitute (-2) for y into (3).

(3)-----> x = 4 - (-2)

x = 4 + 2

x = 6

Therefore, the solution is

(x, y) = (6, -2)

**Problem 4 : **

Solve for x and y :

3x + 5y = - 2

2x - y = 3

**Solution : **

3x + 5y = - 2 -----(1)

2x - y = 3 -----(2)

**Step 1 :**

Solve (2) for y.

2x - y = 3

Subtract 2x from each side.

-y = 3 - 2x

Multiply each side by (-1).

y = 2x - 3 -----(3)

**Step 2 : **

Substitute (2x - 3) for x into (1).

(2)-----> 3x + 5(2x - 3) = -2

3x + 10x - 15 = -2

13x - 15 = -2

Add 15 to each side.

13x = 13

Divide each side by 13.

x = 1

**Step 3 :**

Substitute 1 for x into (3).

(3)-----> y = 2(1) - 3

y = 2 - 3

y = -1

Therefore, the solution is

(x, y) = (1, -1)

**Problem 5 : **

If there is a total of 9 bicycles and unicycles and there are 13 wheels in total, find the number of bicycles and unicycles.

**Solution : **

Let x be the number of bicycles and y be the number of unicycles.

**Given : **There is a total of 9 bicycles and unicycles.

Then,

x + y = 9 -----(1)

**Given : **There are 13 wheels in total.

Then,

2x + y = 13-----(2)

**Step 1 :**

Solve (1) for x.

x + y = 9

Subtract y from each side.

x = 9 - y -----(3)

**Step 2 : **

Substitute (9 - y) for x into (2).

(2)-----> 2(9 - y) + y = 13

18 - 2y + y = 13

18 - y = 13

Subtract 13 from each side.

-y = -5

Multiply each side by (-1).

y = 5

**Step 3 :**

Substitute 5 for y into (3).

(3)-----> x = 9 - 5

x = 4

The solution is

(x, y) = (5, 4)

So, there are 5 bicycles and 4 unicycles.

After having gone through the stuff given above, we hope that the students would have understood how to solve system of equations by substitution.

Apart from the stuff given in this section, if you need any other stuff in math, please use our google custom search here.

HTML Comment Box is loading comments...

You can also visit our following web pages on different stuff in math.

**WORD PROBLEMS**

**Word problems on simple equations **

**Word problems on linear equations **

**Word problems on quadratic equations**

**Area and perimeter word problems**

**Word problems on direct variation and inverse variation **

**Word problems on comparing rates**

**Converting customary units word problems **

**Converting metric units word problems**

**Word problems on simple interest**

**Word problems on compound interest**

**Word problems on types of angles **

**Complementary and supplementary angles word problems**

**Trigonometry word problems**

**Markup and markdown word problems **

**Word problems on mixed fractrions**

**One step equation word problems**

**Linear inequalities word problems**

**Ratio and proportion word problems**

**Word problems on sets and venn diagrams**

**Pythagorean theorem word problems**

**Percent of a number word problems**

**Word problems on constant speed**

**Word problems on average speed **

**Word problems on sum of the angles of a triangle is 180 degree**

**OTHER TOPICS **

**Time, speed and distance shortcuts**

**Ratio and proportion shortcuts**

**Domain and range of rational functions**

**Domain and range of rational functions with holes**

**Graphing rational functions with holes**

**Converting repeating decimals in to fractions**

**Decimal representation of rational numbers**

**Finding square root using long division**

**L.C.M method to solve time and work problems**

**Translating the word problems in to algebraic expressions**

**Remainder when 2 power 256 is divided by 17**

**Remainder when 17 power 23 is divided by 16**

**Sum of all three digit numbers divisible by 6**

**Sum of all three digit numbers divisible by 7**

**Sum of all three digit numbers divisible by 8**

**Sum of all three digit numbers formed using 1, 3, 4**

**Sum of all three four digit numbers formed with non zero digits**