The focus of mathematics in the next period of grade seven is in the first and third chapters. The deformation of several multiplication formulas must be tested.

Example: Given that m-2n = 3 and Mn = 2, find the square of (1)(m+2n)(2)m-the square of Mn+4n.

Solution: Because m-2n = 3 and Mn = 2, the square of (m-2n) = the square of m-the square of -4mn+4n = the square of m -8+4n =9.

So the square of m+the square of 4n = 17.

Square of (1) (m+2n) = square of m+square of +4mn+4n =25.

(2) the square of m-the square of Mn+4n = 15.

Solution of binary linear equations, geometric proof, triangle proof, plane rectangular coordinate system, drawing triangle, etc.

That's all, the problem may lie in geometric proof, triangle proof,