(x+4)²-x²=2x-1
(x+4)²-x²=x²+8x+16-x²
8x+16=2x-1
6x=-17
x=-17/6
x=-2 5/6
x(x²-2)=x³+8
x(x²-2)=x³-2x
x³-2x=x³+8
-2x=8
x=-4
......................................................................
1,2 < a < 1,8 2 < c < 2,5 <span>
3,6<3a<5,4 -2,5<-c<-2
</span>3,6<3a<5,4
-2,5<-c<-2
-------------------
1,1<3a-c<3,4
BC
sin A= -----
AB
BC=AB*sinA
BC=10*0,9=9