How do solve the following linear system?: $4x+3y=1 , 2x +5y - 21 = 0$ ?

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Answer 1 · 2016-04-15T07:43:48

$x=(-116)/28$
$y=41/7$

Given -

$4x+3y=1$ ---------- (1)
$2x+5y-21=0$ -------- (2)

Take the constant term to the left in equation (1)

$4x+3y-1=0$

Let us use elimination method to solve the equations.

Multiply equation (2) with 2

$2x+5y-21=0$ -------- (2) $xx 2$
$4x+10y-42=0$

Equate both the equations

$4x+3y-1=4x+10y-42$

Take constant terms to right and other terms to left.

$4x+3y-4x-10y=-42+1$

Simplify -

$-7y=-41$
$y=(-41)/(-7)=41/7$
$y=41/7$

Substitute $y=41/7$ in equation (1)

$4x+3(41/7)=1$
$4x+123/7=1$
$4x=1-123/7=(-116)/7$

$x=(-116)/7 xx 1/4 = (-116)/28$
$x=(-116)/28$

How do solve the following linear system?: 4x+3y=1 , 2x +5y - 21 = 0 4x+3y=1 , 2x +5y - 21 = 0 ?