How do you solve the system $x = 3 y$ $x=3y$ and $3 x - 5 y = 12$ $3x-5y=12$ using substitution?

Question

How do you solve the system $x = 3 y$ $x=3y$ and $3 x - 5 y = 12$ $3x-5y=12$ using substitution?

1 Answer

Impact of this question

6211 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-03-28T14:35:07

See the entire solution process below:

Explanation:

Step 1) Because the first equation is already solved for $x$ $x$ we can substitute $3 y$ $3y$ for $x$ $x$ in the second equation and solve for $y$ $y$ :

$3 x - 5 y = 12$ $3x - 5y = 12$ becomes:

$(3 \times 3 y) - 5 y = 12$ $(3 xx 3y) - 5y = 12$

$9 y - 5 y = 12$ $9y - 5y = 12$

$(9 - 5) y = 12$ $(9 - 5)y = 12$

$4 y = 12$ $4y = 12$

$\frac{4 y}{4} = \frac{12}{4}$ $(4y)/color(red)(4) = 12/color(red)(4)$

$(color(red)(cancel(color(black)(4)))y)/cancel(color(red)(4)) = 3$

$y = 3$

Step 2) Substitute $3$ for $y$ in the first equation and calculate $x$ :

$x = 3y$ becomes:

$x = 3 xx 3$

$x = 9$

The solution is: $x = 9$ and $y = 3$ or $(9, 3)$

Science

Math

Humanities

... and beyond

How do you solve the system $x = 3 y$ $x=3y$ and $3 x - 5 y = 12$ $3x-5y=12$ using substitution?

1 Answer

Explanation:

Related questions

Impact of this question

Science

Math

Humanities

... and beyond

How do you solve the system x=3yx=3yx=3y and 3x-5y=123x−5y=123x-5y=12 using substitution?

1 Answer

Explanation:

Related questions

Impact of this question

How do you solve the system $x = 3 y$ $x=3y$ and $3 x - 5 y = 12$ $3x-5y=12$ using substitution?