Question

Solve the system of equations using substitution.

4x – y = 7
3y – 12x = –21

(3, 5)

(6, 17)

no solution

infinite solutions

Answer 1

Change the first equation into slope-intercept form.

\(\huge\bf{4x-y=7}\)

Subtract `4x` from each side.

\(\huge\bf{-y=-4x+7}\)

In which we get rid of `-`.

\(\huge\bf{y=4x-7}\)

Lets change the second one is slope-intercept as well to see if they contain different or similar slopes and y-intercepts.

\(\huge\bf{3y-12x=-21}\)

Add `12x`

\(\huge\bf{3y=12x-21}\)

Divide by `3`.

\(\huge\bf{y=4x-7}\)

Since they contain same slopes and y-intercepts what does that tell you?

Answer 2

it has infinite solutions?

Answer 3

Correct :)

Answer 4

thank you:)