Ответ:

Пошаговое объяснение:

446. a=1/23

(a²-64)/a² ·a/(a+8)=((a-8)(a+8))/(a(a+8))=(a-8)/a=1 -8/a=1 -8/(1/23)=1-8·23=1-184=-183

447. a=1/27

(a²-9)/(2a²) ·a/(2a+6)=((a-3)(a+3))/(2a·2(a+3))=(a-3)/(4a)=1/4 -3/(4a)=1/4 -3/(4·1/27)=1/4 -(3·27)/4=(1-81)/4=-80/4=-20

448. x=1/5, y=1/8

((4y)/(5x) -(5x)/(4y))÷(4y+5x)=((16y²)/(20xy) -(25x²)/(20xy)) ·1/(4y+5x)=((4y-5x)(4y+5x))/(20xy) ·1/(4y+5x)=(4y-5x)/(20xy)=1/(5x) -1/(4y)=1/(5·1/5) -1/(4·1/8)=1 -1/(1/2)=1-2=-1

449. x=1/6, y=1/9

((2y)/x -x/(2y))÷(2y+x)=((4y²)/(2xy) -x²/(2xy))·1/(2y+x)=((2y-x)(2y+x))/(2xy) ·1/(2y+x)=(2y-x)/(2xy)=1/x -1/(2y)=1/(1/6) -1/(2·1/9)=6 -9/2=6-4,5=1,5

450. x=1/8, y=1/4

(y/(4x) -(4x)/y)÷(y+4x)=(y²/(4xy) -(16x²)/(4xy))·1/(y+4x)=((y-4x)(y+4x))/(4xy) ·1/(y+4x)=(y-4x)/(4xy)=1/(4x) -1/y=1/(4·1/8) -1/(1/4)=2-4=-2

451. x=1/3, y=1/4

((2y)/(3x) -(3x)/(2y))÷(2y+3x)=((4y²)/(6xy) -(9x²)/(6xy)) ·1/(2y+3x)=((2y-3x)(2y+3x))/(6xy) ·1/(2y+3x))=(2y-3x)/(6xy)=1/(3x) -1/(2y)=1/(3·1/3) -1/(2·1/4)=1-2=-1