Question

Срочно!!! даю много баллов

Answer 1

Ответ:

Объяснение:

1. При b=-15/16:

(64b²+128b+64)/b ÷(4/b +4)=((8b)²+2·8b·8+8²)/b ÷(4+4b)/b=(64(b+1)²)/b ·b/(4(b+1))=16(b+1)=16b+16=16·(-15/16) +16=-15+16=1

2. При a=-5:

(a +1/a +2)·1/(a+1)=(a²+1+2a)/a ·1/(a+1)=(a+1)²/a ·1/(a+1)=(a+1)/a=(-5+1)/(-5)=(-4)/(-5)=0,8

3. При a=1; b=1/3:

(b/a -a/b)·1/(b+a)=(b²-a²)/(ab) ·1(b+a)=((b-a)(b+a))/(ab) ·1/(b+a)=-(a-b)/(ab)=-(1 -1/3)/(1·1/3)=-(3/3 -1/3)/(1/3)=-2/3 ·3/1=-2

4. При a=-39:

(a³-25a)(1/(a+5) 1/(a-5))=a(a²-25)((a-5)-(a+5))/((a+5)(a-5))=a(a²-25)(a-5-a-5)/(a²-25)=a·(-10)=-10a=-10·(-39)=390

5. При x=1/7; y=1/4:

(y/(5x) -(5x)/y)÷(y+5x)=(y²-(5x)²)/(5xy) ·1/(y+5x)=((y-5x)(y+5x))/(5xy) ·1/(y+5x)=-(5x-y)/(5xy)=(5·1/7 -1/4)/(5·1/7 ·1/4)=(20/28 -7/28)/(5/28)=13/28 ·28/5=13/5=2,6