-4 (2,5a-1,5)+5,5a-8 при a=-2/9

Question

-4 (2,5a-1,5)+5,5a-8 при a=-2/9

Answer 1

-4 (2,5a-1,5)+5,5a-8
-10a+6+5,5a-8
-4,5a-2
-4,5*(-2/9)-2
-45/10*(-2/9)-2
(45*2/ 10*9)-2
(5×2/10*1)-2
(2/2)-2
1-2=-1

Comments

а откуда 6 ?

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-1,5*-4=6

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спасибо