{2x+3y = 7, if the first formula is brought into the second, the result is (3y+ 1)+3y=7, y= 1.

I take the first one as an example to solve the binary linear equations (two unknowns X and Y). The key is to express one of the unknowns (such as X) as the relationship of another with one formula (such as x= 1.5y+0.5), and then bring it into another formula to solve Y, which is the method of addition, subtraction and elimination. Understand? Practice the rest of the questions and you will be skilled! {m-n two thirds =2, {2m+3n = 12.

For this group, because there is an unknown number n(n can't be 0) in the denominator, we should pay attention to the range of this unknown number when solving the problem. Others are technical things, such as

{3x- 13y=- 16

{x+3y = 2, you can multiply the left and right sides of the second formula by 3, that is, 3(x+3y)=3(2), remove the brackets to 3x+9y=6, then move the term to 3x=6-9y, and then bring the 3x whole into the first equation, that is, (6-9y)-655. X =- 1。 {4x-3y =-4, {four tenths of x+three tenths of y =6} This set of equations belongs to a binary quadratic system, which cannot be solved by the current method. I hope you practice the basic methods more, and then summarize the skills when you are proficient. Step by step, I suggest you consult more teachers or classmates and learn and make progress in the process of communication. In short, I ..