Question

Solve the following systems of equations:
0.4x + 0.3y = 1.7
0.7x - 0.2y = 0.8

Answer 1

Given pair of linear equations:

0.4x + 0.3y = 1.7………(1)

0.7 x  - 0.2y= 0.8………(2)

Elimination method is used to solve this Linear pair of Equations:

On multiplying equation (1) by 20 and equation (2) by 30 :  

8x + 6y = 34………..(3)

21x - 6y = 24………..(4)

On adding equations (3) and (4) :

8x + 6y = 34

21x - 6y = 24

------------------

29x = 58

x = 58/29

x = 2

On putting x= 2 in eq (2)  we get,

0.7 x  - 0.2y= 0.8

0.7(2) - 0.2y = 0.8

1.4 - 0.2y = 0.8

0.2y = 0.8 - 1.4

0.2y = 0.6

y = 0.6 /0.2

y = 3

Hence, the value of the given system of equation is x = 2  and y = 3.

Hope this answer will help you…

 

Some more similar questions from this chapter :  

Solve the following systems of equations:

3x-7y+10=0

y-2x-3=0

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Solve the following systems of equations:

11x+15y+23=0

7x-2y-20=0

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Answer 2

Answer:

0.4 x + 0.3y = 1.7 (multiply by 7)

2.8 x + 2.1 y = 11.9 ----- equ 1

0.7 x - 0.2 y = 0.8 ( multiply by 4)

2.8 x - 0.8 y = 3.2 ------ equ 2

Solving 1 and 2

2.8 x + 2.1 y = 11.9

2.8 x - 0.8y = 3.2

--------------------------

2. 9 y = 15.1

y = 15.1/2.9

y = 5.2

Substitute the value of y = 5.2 in first given equation.

0.4 x + 0.3y = 1.7

0.4 x + 0.3(5.2) = 1.7

0.4 x + 1.56 = 1.7

0.4 x = 1.7 - 1.56

0.4 x = 0.14

x = 0.14/0.4

x = 0.34

Sorry for the late response..

I hope it will help you mate!