Помогите решить 7,8,9!!!!!

Question

Помогите решить 7,8,9!!!!!

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Answer 1

7) I1-2*0.7I - I0.7I = 0.4-0.7= -0.3
8) А = - 3,13; В = -2/3; С = -13/5
9) (5625/1000 * 4/3 - 65/18 * 9/5) * 3/5 = (225/30 - 585/75) * 3/5 = 
= 3/10 * 3/5 = 9/50 = 0,18