Question

8- Utilizando os princípios multiplicativo e/ou aditivo, calcule a solução (raiz) das seguintes equações, sendo U= Q
a) 2x + 12 = 20
b) 5x -5 = 12
c)-2x - 1 = 10
d) 5x - 7 = x

É URGENTE POR FAVOR AJUDEM!!​

Answer 1

$\large\boxed{\begin{array}{l}\tt a)~\sf 2x+12=20\\\sf 2x+12-\boxed{\sf12}=20-\boxed{\sf12}\\\sf 2x=8\\\sf 2x\cdot\boxed{\dfrac{1}{2}}=8\cdot\boxed{\sf\dfrac{1}{2}}\\\sf x=4\end{array}}$

$\large\boxed{\begin{array}{l}\tt b)~\sf 5x-5=12\\\sf 5x-5+\boxed{\sf5}=12+\boxed{\sf5}\\\sf 5x=17\\\sf5x\cdot\boxed{\sf\dfrac{1}{5}}=17\cdot\boxed{\sf\dfrac{1}{5}}\\\\\sf x=\dfrac{17}{5}\end{array}}$

$\large\boxed{\begin{array}{l}\tt c)~\sf-2x-1=10\\\sf -2x-1+\boxed{\sf1}=10+\boxed{\sf1}\\\sf -2x=11\\\sf -2x\cdot\boxed{-\sf\dfrac{1}{2}}=11\cdot\boxed{-\dfrac{1}{2}}\\\sf x=-\dfrac{11}{2}\end{array}}$

$\large\boxed{\begin{array}{l}\tt d)~\sf 5x-7=x\\\sf 5x-7+\boxed{\sf7}=\boxed{\sf7}+x\\\sf 5x=\boxed{7}+x\\\sf 5x-\boxed{\sf x}=7+x-\boxed{\sf x}\\\sf 6x=7\\\sf 6x\cdot\boxed{\sf\dfrac{1}{6}}=7\cdot\boxed{\sf\dfrac{1}{6}}\\\sf x=\dfrac{7}{6}\end{array}}$