Question

Срочно!!!Дам 80 баллов!!!

Answer 1

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$1)\; \; (6y+15)(2,4-0,8y)=0\\\\6y+15=0\; \; \to \; \; \; 6y=-15\; ,\; \; y=-\frac{5}{2}\; ,\; \; \underline {\; y=-2,5\; }\\\\2,4-0,8y=0\; \; \to \; \; 2,4=0,8y\; ,\; \; \underline {\; y=3\; }\\\\\\2)\; \; 12x-(5x-8)=8+7x\\\\12x-5x+8=8+7x\\\\12x-5x-7x=8-8\\\\0\cdot x=0\\\\0=0\; \; pri\; \; \underline {\; x\in (-\infty ,+\infty )\; }$