2a²-5a-8-(a+3)(a-3)+5(a-2)=2(a-2)(a-3)
(=)2a²-5a-8-(a+3)(a-3)+5(a-2)-2(a-2)(a-3)=0
(=)2a²-5a-8-a²+9+5a-10-2(a²-3a-2a+6)=0
(=)2a²-5a-8-a²+9+5a-10-2(a²-5a+6)=0
(=)2a²-5a-8-a²+9+5a-10-2a²+10a-12=0
(=)-a²+10a-21=0
(=)-a²+3a+7a-21=0
(=)-a(a-3)+7(a-3)=0
(=)(-a+7)(a-3)=0
(=)[−a+7=0a−3=0[−a+7=0a−3=0 (=)[a=7a=3[a=7a=3
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