Question

потрібна відповідь срочно​

Answer 1

$7)y = 7x {}^{2} + 21x$

$y = 7(x {}^{2} + 3x)$

$y + ? = 7(x {}^{2} + 3x + ? )$

$y + ? = 7(x {}^{2} + 3x + \frac{9}{4} )$

$y + 7 \times \frac{9}{4} = 7(x {}^{2} + 3x + \frac{9}{4} )$

$y + \frac{64}{4} = 7(x + \frac{3}{2} ) {}^{2}$

$y = 7(x + \frac{3}{2} ) {}^{2} - \frac{63}{4}$