What is the solution of $y = 3x - 4$ and $2x - y = 1$ ?

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Answer 1 · 2018-06-04T13:45:20

$x=3, y=5$

Rearrange to make $y$ the subject

$2x-y=1 =>y=2x-1$

Now you have two equations with $y=$ so equate them

$3x-4=2x-1$

Add 4 to both sides

$3x=2x+3$

Subtract $2x$ from both sides

$x=3$

Substitute $x=3$ into $y=3x-4 => y=9-4, y=5$

Answer 2 · 2018-06-04T13:45:59

$x=3 and y=5$

Notice that there is a single $y$ term in each equation,

Make $y$ the subject in each case.

$color(blue)(y = 3x-4)" "and" "color(red)(y =2x-1)$

We know that $" "color(blue)(y) = color(red)(y)$

$:." "color(blue)( 3x-4)" "=" "color(red)(2x-1)$

$color(white)(xxxxxx)3x-2x = -1+4$

$color(white)(xxxxxxxxxxx)x = 3$

$y=2x-1$

$y = 2(3)-1 = 5$

What is the solution of y = 3x - 4y = 3x - 4 and 2x - y = 12x - y = 1?