Выражение а) -21×(4-10)-54а б) 28-10d+4×(d+18)

А) -84+210-54а= 126-54а
б) 28-10d+4d+72=100-6d

А) -21*(4-10)-54а= -21*(-6)-54а= 126- 54а
б) 28-10d+4*(d+18)= 28-10d+ 4d+ 72= 100-6d

1a)(3c+2)/(c²-4c+4) -5/(c-2)=(3c+2)/(c-2)²-5/(c-2)=(3c+2-5c+10)/(c-2)²=(12-2c)/(c-2)²
б)2mn/(m³+n³)+2m/(m²-n²) -1/(m-n)=2mn/(m+n)(m²-mn+n²)+2m/(m-n)(m+n)-1/(m-n)=
=(2m²n+2mn²+2m³-2m²n+2mn²-m³-n³)/(m-n)(m+n)(m²-mn+n²)=
=(m³-n³)/(m²-n²)(m²-mn+n²)=(m-n)(m²+mn+n²)/(m-n)(m+n)(m²-mn+n²)=
=(m²+mn+n²)/(m³+n³)
в)3a(16-3a)/(9a²-4) + 3(1+2a)/(2-3a) -(2-9a)/(3a+2)=
=(48a-9a²-3-9a-12a-18a²-6a+4+27a²-18a)/(9a²-4)=(3a-2)/(3a-2)(3a+2)=1/(3a+2)
г)(y²+4)/(y³+8) -1/(y+2)=(y²+4-y²+2y-4)/(y³+8)=2y/(y³+8)

2a)(x²-y²)/3xy*3y/(x-y)=(x-y)(x+y)/3xy * 3y/(x-y)=(x+y)/x
б)(c²-49)/10cd :(2c+14)/5d=(c-7)(c+7)/10cd*5d/2(c+7)=(c-7)/4c
в)(x²-10x+25)/(3x+12) : (2x-10)/(x²-16)=(x-5)²/3(x+4) * (x-4)(x+4)/2(x-5)=(x-5)(x-4)/6
г)(t³+8)/(12t²+27t) * (4t+9)/(t²-2y+4)=(t+2)(t²-2t+4)/3t(4t+9) * (4t+9)/(t²-2t+4)=(t+2)/3t

1                 0,16                  53,4(15                     16,94(2,8
             *   0,25                  -45             - 168   
                         3,56                 6,054
               0,0400                    84                               140
                                          -  75                           -   140
                                                                    
                                              90                                 0
                                        -     90
                                          
                                               0