Application of Systems of Linear Equations in Two

VariablesBy Sri Handayani

• Application SLETV that using to

solve the problems that related

daily life

• problems are usually presented in

word problems

To solve word problem, we can change a word

problem to be mathematical model

change the unknown quantities with variables

Translate the statements relating unknown

quantities into the mathematical language

Example 1:

In the buying and selling activities, Sari buy 2 books

dan 3 pencils so she will pay Rp.8500 and Weni buy 3

books and 1 pencil, Weni pay Rp. 7500.

a. Build its to mathematical model !

b. Find the total price of 4 books and 2 pencils!

a)

For 2 books and 3 pencils is 8500

For 3 books and 1 pencil is 7500

Consider the price 1 book is x and 1 pencil is y

b. ) 2x + 3y = 8500 …..1st equation

3x + y = 7500 ……2nd equation

Elimination Method

2x + 3y = 8500 (x1) 2x + 3y = 8500

3x + y = 7500 (x3) 9x + 3y = 22500

-7x = -14000

x = 2000

Substitution Method :

x = 2000 subtitution to 2nd equation

3x + y = 7500

3(2000) + y = 7500

6000 + y = 7500

6000 – 6000 + y = 7500 – 6000

y = 1500

So, price of 1 book is Rp. 2000 and price 1 pencil is Rp. 1500

Thus, 4x + 2y = 4(2000) + 2(3000) = 8000 + 6000 = 14000

2. Circumference of land shaped

rectangle is 48 m. the length over

6 meters than width. Determine

the area of the land!