Substitution
Substitution is the act of substituting variables for actual numbers. Here's the run down:
- In algebra, variables (letters) hold the place of a number that is unknown.
- We can substitute numbers in for the variables (substitution)
Example: 16x-8x+5y= ? (x=5 y=3)
Substitution: 16(5)-8(5)+5(5)=?
16(5)= 80
8(5)= 40
5(5)= 25
80-40+25= 65
The answer to this equation is 65. First we substituted the numbers in for the variables. Then we followed the order or operations*. We solved the parentheses and then we subtracted 80 from 40 to get 40. Then we added 25 to 40 to get 65.
*Order of Operation
1.Parentheses
2.Exponents
3.Multiplication & Division
4.Addition & Subtraction
Substitution: 16(5)-8(5)+5(5)=?
16(5)= 80
8(5)= 40
5(5)= 25
80-40+25= 65
The answer to this equation is 65. First we substituted the numbers in for the variables. Then we followed the order or operations*. We solved the parentheses and then we subtracted 80 from 40 to get 40. Then we added 25 to 40 to get 65.
*Order of Operation
1.Parentheses
2.Exponents
3.Multiplication & Division
4.Addition & Subtraction