Question

Which is the best first step and explanation for solving this system of equations?

Answer 1

Subtract equation 1 from equation 2

Explanation:

Solve the following system:

{3 x + 4 y = 12 | (equation 1)

3 x = 2 y - 8 | (equation 2)

Express the system in standard form:

{3 x + 4 y = 12 | (equation 1)

3 x - 2 y = -8 | (equation 2)

Subtract equation 1 from equation 2:

{3 x + 4 y = 12 | (equation 1)

0 x - 6 y = -20 | (equation 2)

Divide equation 2 by -2:

{3 x + 4 y = 12 | (equation 1)

0 x+3 y = 10 | (equation 2)

Divide equation 2 by 3:

{3 x + 4 y = 12 | (equation 1)

0 x+y = 10/3 | (equation 2)

Subtract 4 × (equation 2) from equation 1:

{3 x+0 y = (-4)/3 | (equation 1)

0 x+y = 10/3 | (equation 2)

Divide equation 1 by 3:

{x+0 y = (-4)/9 | (equation 1)

0 x+y = 10/3 | (equation 2)

Collect results:

Answer: {x = -4/9 , y = 10/3