Question

7) Se x + y = 11 e x - y = 5, então o valor da expressão x² - y² é:​

Answer 1

$\geqslant \: resolucao \\ \\ x + y = 11 \\ x - y = 5 \\ \\ 2x = 16 \\ x = \frac{16}{2} \\ x = 8 \\ \\ y = 11 - x \\ y = 11 - 8 \\ y = 3 \\ \\ = = = = = = = = = = = = = = = = = \\ \\ = {x}^{2} - y {}^{2} \\ = 8 {}^{2} - 3 {}^{2} \\ = 64 - 9 \\ = 55 \\ \\ \\ \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \geqslant$