y = 3x+5 (I)
4x + 2y = 30 y ( II)
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SUBSTITUTION (we will replace one equation in the other )
1) we can substitute y in (II) using the equation (I)
4x + 2y = 30 y ( II)
Replacing y by y = 3x+5
4x + 2(3x +5 ) = 30(3x +5 )
Now, we have an equation with just one unknown term x
finding x
4x + 2(3x +5 ) = 30(3x +5 )
4x + 6x + 10 = 90 x + 150
90 x - 6x -4x = 10 - 150
(90 - 10) x = -140
80 x = - 140
x= - 140/ 80 = -7/4 = - 1.75
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Now, y
we can just replace the value in (I)
y = 3 (-1.75 )+5
y = - 5.25 + 5
y = -1/4 = - 0.25
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Answer
x= -7/4 = - 1.75
y = -1/4 = - 0.25
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Verifying (we can replace the value in (II))
4(-0.25) + 2 (-1.75) = 30 (1. 75 ) ( II)
4(-0.25) + 2 (-1.75) = 30 (-1. 75 )
-1 +2* = - 52. 5