$$ \begin{aligned} 4-2(5x+3)-5\cdot(8+2x) &= 0&& \text{simplify left side} \\[1 em]4-(10x+6)-(40+10x) &= 0&& \\[1 em]4-10x-6-(40+10x) &= 0&& \\[1 em]-10x-2-(40+10x) &= 0&& \\[1 em]-10x-2-40-10x &= 0&& \\[1 em]-20x-42 &= 0&& \text{ move the constants to the right } \\[1 em]-20x &= 42&& \text{ divide both sides by $ -20 $ } \\[1 em]x &= -\frac{42}{20}&& \\[1 em]x &= -\frac{21}{10}&& \\[1 em] \end{aligned} $$

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