The solution is $a=-6$.
Work Step by Step
$\sqrt -5a+6=-a$ Square both sides: $-5a+6=a^2$ $a^2+5a-6=0$ $a-1=0$ or $a+6=0$ $a=1$ or $a=-6$ Check: $\sqrt -5(1)+6=-1$ $1=- 1$ $\sqrt -5(-6)+6=-(-6)$ $6=6$ The solution is $a=-6$.
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