Question

Calcule: (1,5 pontos)​

Answer 1

Resposta:

x= -76

Explicação passo-a-passo:

$Antes\,fatoramos:\\27=3^3\\243=3^5\\\\27^{3x-42}=243^{2x-10}\\(3^3)^{3x-42}=(3^5)^{2x-10}\\3^{9x-126}=3^{10x-50}\\9x-126=10x-50\\-10x+9x=-50+126\\-x=76\,\,\,*(-1)\\\boxed{x= -76}$