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Question
Solve the following systems of equations:
0.4x + 0.3y = 1.7
0.7x − 0.2y = 0.8
Solution
The given system of equation i
0.4x + 0.3y = 1.7 ......(i)
0.7x − 0.2y = 0.8 .....(ii)
Multiplying both sides of (i) and (ii), by 10, we get
4x + 3y = 17 ....(iii)
7x - 2y = 8 ......(iv)
From (iv), we get
7x = 8 + 2y
`=> 7x (8 + 2y)/7`
Substituting `x = (8 + 2y)/7` in (iii) we get
`4((8+2y)/7) + 3y = 17`
`=> (32 + 8y)/7 + 3y = 17`
=> 32 + 29y = 17 x 7
=> 29y = 119 - 32
=> 29y = 87
`=> y = 87/29 = 3`
Putting y = 3 in `x = (8 + 2y)/7` we get
`x = (8 + 2 xx 3)/7`
`= (8 + 6)/7`
`= 14/7`
= 2
Hence, the solution of the given system of equation is x = 2, y = 3
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