Simplification (x ^ 2-2y ^ 2-z ^ 2) - (- y ^ 2 + 3x ^ 2-z ^ 2) + (5x ^ 2-y ^ 2 + 2Z ^ 2) kuai

Simplification (x ^ 2-2y ^ 2-z ^ 2) - (- y ^ 2 + 3x ^ 2-z ^ 2) + (5x ^ 2-y ^ 2 + 2Z ^ 2) kuai

(x^2—2y^2-z^2)—(-y^2+3x^2—z^2)+(5x^2—y^2+2z^2)
=x^2-2y^2-z^2+y^2-3x^2+z^2+5x^2-y^2+2z^2
=3x^2-2y^2+2z^2

1. The following equation is a.x + xy = 1, b.7x = y

B
Bivariate linear equation: if an equation contains two unknowns and the exponent of the unknowns is 1, then the integral equation is called bivariate linear equation with infinite solutions. The general form of bivariate linear equation is ax + by + C = 0 (a, B are not 0)

Given the equation 7x-5y = 3, the algebraic expression of X is used to express Y: y =?

5y=7x-3 x=(7x-3)/5