По теореме Пифагора ВС=√(5²-4²)=3
sinA=BC/AB=3/5=0,6
2) 3-a+2(3-2)=3-a+2×1=3-a+2=5-a
4) x-y-4(x-y)=x-y-4x+4y=-3x+3y
6) 5x(x+y)+x+y=(x+y)(5x+1)
8) c(m-n)+m-n=(m-n)(c+1)
1. х^2-25= (х-5)(х+5).
2. 36m^2-100n^2= (6m-10n)(6m+10n).
3. (4-y)^2= 16-8y+y^2.
4. 36a^2+24ab+4b^2= (6a+2b)^2.
2x-3>3x-4
2x-3x>-4+1
-x>-3
x<1