Solve for x: 3x + 4y = 85 ; 6x + 7y = 20

Linear equations in two variables are in the form of ax + by + c = 0 where a, b, c are real numbers and a, b ≠ 0.

Answer: Solving for x in  3x + 4y = 85 ; 6x + 7y = 20 we have x  =  -515/3

Here's the detailed solution.

Explanation:

Let 3x + 4y = 85 be eq 1; 

and 6x + 7y = 20 be eq 2

To solve these equations we will multiply eq 1 by 2 and let the resultant equation be eq 3.

i.e., 6x + 8y = 170 is eq 3

By subtracting eq 2 from eq 3, we get

⇒ y = 150

By using the value of y in eq 2 we get

6 x + 7 (150) = 20

6 x = 20 - 1050

6 x = - 1030

x = - 1030 / 6

x = -515/3

Thus, the value of x for the equations is -515/3.