1. Math D Block SYSTEM OF EQUATIONS SOL CHOI

2. What is System of Equations? System of equations is a collection of two or more equations with a same set of unknowns. For example… I have to buy total 100 candies and chocolates for Halloween Party. Candy cost 10Tk for each and chocolate cost 20Tk for each. I paid 1400Tk for candies and chocolates. How many chocolates I got? x + y=100 { 10x + 20y = 1400 -10x + -10y = -1000 + 10x + 20y = 1400 --------------------------------- 10y = 400 = 1y = 40 Candy = x Chocolate = y

3. HOW to Solve it..? There are two ways to solve system of equations. The method of addition and subtraction It is a way to erase one Unknown. 2x + 3y = 8 { 2x + 7y = 16 2x + 3y = 8 - 2x + 7y = 16 - - - 4y = - 8 y = 2 x = 1 2x + 3y = 8 2x + 6 = 8 2x = 2 x = 1

4. The method of substitution x + 3y = 11 { Make a equation of x or y. And put that equation in other Equation. Than you can have only one Unknown., 2x + 7y = 25 x = 11 – 3y 2(11 – 3y) + 7y = 25 22 – 6y + 7y = 25 - 6y + 7y = -22 + 25 Y = 3 X = 2 x + 9 = 11 11- 9 = x 2 = x

5. If..it has more than 2 Equations…;; 7x + y = 6x + 3y + 1 = 2x + 4y + 12 7x + y = 6x + 3y + 1 7x + y = 2x + 4y + 12 { You can just divide it into 2 System of equations. They are all equal. Sometimes, you can see the equations that Has more than two equations.

6. ~Thanks for watching~