Question

Examine the system of equations. −3x + y = 9, 2x + 4y = 8 Which variable is most efficient to isolate?

Answer 1

Good morning ☕️

Answer:

(-2 , 3)

Step-by-step explanation:

It’s easier to isolate y in the first equation because the coefficient of y there is just 1.

the coefficient of x in the first equation is -3 and in the second equation is 2 then it’s not easy to isolate x in both equation.

solving the system:

−3x + y = 9

2x + 4y = 8

⇔

y = 3x + 9  (*)

2x + 4y = 8

now, we substitute y by 3x + 9 in equation 2:

2x + 4(3x + 9) = 8  ⇔ 14x + 36 = 8 ⇔ 14x = - 28 ⇔ x = -28/14 = -2

at this stage we substitute x by -2 in (*) to get y:

y = 3x + 9 ⇒ y = 3(-2) + 9 = -6 + 9 = 3

finally, the solution of the system is the ordered pair (-2 , 3).

_____________________________________________

:)

Answer 2

the y in the first equation