Question

×+80=120-× regra de 3 me ajudem pfv do falta 2 duas para a prova e matemática

Answer 1

Resposta:

Vamos suplementar esses ângulos, com y;

$1^{o}.\\x+80^{o}+y=180^{o}\\x+y=180^{o}-80^{o}\\x+y=100^{o}\\\\2^{o}.\\120^{o}-x+y=180^{o}\\-x+y=180^{o}-120^{o}\\-x+y=60^{o}\\\\Sistema;\\\left \{ {{x+y=100^{o}} \atop {-x+y=60^{o}}} \right.\\\\x-x+y+y=100^{o}+60^{o}\\2y=160^{o}\\y=\frac{160^{o}}{2}\\y=80^{o}$

Substituindo em [ x + 80º + y = 180º ] .

$x+80^{o}+y=180^{o}\\x+80^{o}+80^{o}=180^{o}\\x+160^{o}=180^{o}\\x=180^{o}-160^{o}\\\boxed{x=20^{o}}\\\\Provando;\\x+80=120-x\\20+80=120-20\\\boxed{100}=\boxed{100}$

Explicação passo-a-passo: