Vgln. eerste graad (reeks 5)

Alles samen. Gebruik stappenplan en ZRM!

\(-4(-3x-\frac{5}{7})=5x+\frac{8}{7}\)

\(\text{(1) Haakjes (2) Breuken weg (3) + - (4) . /} \\ \begin{align} & \color{red}{-4} (-3x-\frac{5}{7})& = & 5x+\frac{8}{7} \\\Leftrightarrow & 12x+\frac{20}{7}& = & 5x+\frac{8}{7} \\ & & & \text{kgv van noemers 7 en 7 is 7} \\\Leftrightarrow & \color{blue}{7} .(\frac{84}{ \color{blue}{7} }x+ \frac{20}{ \color{blue}{7} })& = & (\frac{35}{ \color{blue}{7} }x+ \frac{8}{ \color{blue}{7} }). \color{blue}{7} \\\Leftrightarrow & 84x \color{red}{+20} & = & \color{red}{35x} +8 \\\Leftrightarrow & 84x \color{red}{+20} \color{blue}{-20} \color{blue}{-35x} & = & \color{red}{35x} +8 \color{blue}{-35x} \color{blue}{-20} \\\Leftrightarrow & 84x-35x& = & 8-20 \\\Leftrightarrow & \color{red}{49} x& = & -12 \\\Leftrightarrow & x = \frac{-12}{49} & & \\ & V = \left\{ \frac{-12}{49} \right\} & \\\end{align}\)