Question

x²+3y²+4x-y² пожалуйста срочнооо​

Answer 1

$x {}^{2} + 3y {}^{2} + 4x - y { }^{2} = x {}^{2} + 4x + \underbrace{3y {}^{2} - y {}^{2} } _{2y {}^{2} } = x {}^{2} + 4x + 2y {}^{2} .$