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\begin{aligned}4(x-3)+12 &=15-5(x+6) & & \\4 x-12+12 &=15-5 x-30 & & \text { Apply the distributive property. } \\4 x &=-15-5 x & & \text { Combine like terms. } \\9 x &=-15 & & \text { Place } x \text {-terms on one side and simplify. } \\x &=-\frac{15}{9} & & \text { Multiply both sides by } \frac{1}{9}, \text { the reciprocal of } 9 . \\x &=-\frac{5}{3} & &\end{aligned}