Question

what is substitution method and how we can use it

Answer 1

actually my friend substitution method is a method which is used in Algebra are you can see a linear equation in two variables or it is given in maths NCERT class 10th page number 46 but it can where is pace to pace my friend if a question is X + Y and it value is equal to one another question is action perfect why 1 is equal to two you can substitute the value of any anyone equation and you can put them in such that you can substitute those values and my friend BB in my team and together we will rule the universe

Answer 2

Substitution method


System of linear equations can also be solved using the substitution method.We will show with examples.

Before you learn this lesson, make sure you understand how to solve linear equatioon.

Example 1 : Solve the following system using the substitution method

x + y = 20
x − y = 10

Step 1

You have two equations. Pick either the first or the second equation and solve for either x or y

Since I am the one solving it, I have decided to choose the equation at the bottom (x − y = 10) and I will solve for x

x − y = 10

Add y to both sides

x − y + y = 10 + y

x = 10 + y

Step 2

Since you used the equation at the bottom to solve for x, you will substitute x into the equation on top (x + y = 20)

Using x + y = 20, erase x and write 10 + y since x = 10 + y

We get 10 + y + y = 20

10 + 2y = 20

Minus 10 from both sides

10 − 10 + 2y = 20 − 10 

2y = 10

Divide both sides by 2

y = 5

Now you have y, you can replace its value into either equation to get x

Replacing y into x + y = 20 gives

x + 5 = 20

Minus 5 from both sides

x + 5 − 5 = 20 − 5

x = 15

The solution to the system is x = 15 and y = 5

Indeed 15 + 5 = 20 and 15 − 5 = 10