-2/9 + 5/6=5*3/18- 2*2/18=11/18
-1 3/4-2 1/12=-(1 3/4+2 1/12)=-(21/12+25/12)=-(46/12)=-3 10/12=-3 5/6.
-5/6+3/8=-20/24+9/24=-11/24
-2 5/7-1 1/14=-(19*2/14+15/14)=--53/14=-3 11/14
1) (х+9)*(-2) = -2*(х+9)
2) (17+3)*(-3) = -51-(3)у
(17+у)*(-3) = -3(17+у)
-(-x)=9.4
-(-16)≠9.4
задача неверна.
C²(2b+a)-4(2b+a)=(c²-4)(2b+a)