Solve by Substitution y=3x , 9x-3y=0

$y = 3 x$ , $9 x - 3 y = 0$

Step 1

Replace all occurrences of $y$ with $3 x$ in each equation.

Replace all occurrences of $y$ in $9 x - 3 y = 0$ with $3 x$ .

$9 x - 3 (3 x) = 0$

$y = 3 x$

Simplify the left side.

Simplify $9 x - 3 (3 x)$ .

Multiply $3$ by $- 3$ .

$9 x - 9 x = 0$

$y = 3 x$

Subtract $9 x$ from $9 x$ .

$0 = 0$

$y = 3 x$

$0 = 0$

$y = 3 x$

$0 = 0$

$y = 3 x$

$0 = 0$

$y = 3 x$

Step 2

Remove any equations from the system that are always true.

$y = 3 x$

Step 3

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