1) (a) (2x-1)^2 = 4x^2-4x+1
1) (б) (3а+с)^2 = 9a^2+6ac+c^2
1) (в) (y-5)×(y+5) = y^2-25
1) (г) (4b+5c)×(4b-5c) = 16b^2-25c^2
2) (x+y)×(x-y)-(x^2+3y^2) = x^2-y^2-x^2-3y^2 = (-4y^2)
3) (a) 16y^2-0.25 = 16 y^2 - 1/4 = (4y-1/2)×(4y+1/2)
3) (б) a^2+10ab+25b^2 = (a+5b)^2
4) (a) (5-x)^2-x×(2.5+x) = 0
25-10x+x^2-2.5x-x^2 = 0
25-12.5x = 0
-12.5x = -25
x = 2
4) (б) 100x^2-16 = 0
100x^2 = 16
x1 = -2/5
x2 = 2/5
5) (a) (2a-b^2)×(2a+b^2) = 4a^2-b^4
5 (б) (х-6х^3)^2 = х^2-12х^4+36х^6 = 36х^2-12х^4+х^2
5 (в) (y+b)^2×(y-b)^2 = y^4-2b^2y^2 + b^4
:)