How do solve the following linear system?: −7x+y=−19,x−3y=−6?

1 Answer
Shiva Prakash M V
Mar 31, 2018

Hence, the values of x and y are
(x,y)≡(6320,6120)

Explanation:

−7x+y=−19.........(1)

x−3y=−6..........(2)

Eliminating x from (2)

x=3y−6

Substituting for x in (1)

−7x+y=−19

−7(3y−6)+y=−19

−7×3y+7×6+y=−19

−21y+42+y=−19

(−21y+y)=−19−42

−20y=−61

y=6120

x=3y−6

x=3×6120−6

x=3×6120−6×2020

x=183−12020

x=6320

Checking,,

−7x+y=−19

lhs=
−7x+y=
−7×6320+6120
=−7×63+6120
=−441+6120
=−38020
=−19
=rhs

x−3y=−6

lhs=
x−3y=
6320−3×6120

=63−3×6120

63−18320

−12020

=−6

=rhs

Hence, the values of x and y are
(x,y)≡(6320,6120)

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