3√2*√5*4√10
сначала
3√2*√5=3√10
дальше
3√10*4√10=12√100=12*10=120
(4x²-y²) + (2x-y) = (2x-y)(2x+y) + (2x-y) = (2x-y)(2x+y+1)
1) c²-0,49=(c-0,7)(c+0,7)
2) 16-k²=(4-k)(4+k)
3) 400-m²=(20-m)(20+m)
4) t²-225=(t-15)(t+15)
5) 1,69-b²=(1,3-b)(1,3+b)
6) y²-16/81=(y-4/9)(y+4/9)
7) 25x²-4=(5x-2)(5x+2)
8) 25/36-64y²=(5/6-8y)(5/6+8y)
X^2+17x+72/x+9=-1
x+17x+72+9=-1
18x=-72-9-1
18x=-90
x=5