A³-4a=a(a²-4)=a(a+2)(a-2)
ax²-ay²=a(x²-y²)=a(x+y)(x-y)
3a²-6ab+3b²=3(a²-2ab+b²)=3(a-b)(a-b)=3.(a-b)²
ax²+ax+a=a(x²+x+1)
x²+7x=0, x(x+7)=0, x1=0,x2=-7
x²-25=0, (x+5)(x-5)=0, x1=-5,x2=5
2) (4x -y)² -(4x+y)² ? x=1 1/8 =( 1*8+1/)8 =19/8 b=-0,2.
(4x -y)² -(4x+y)² =(4x-y-(4x+y))(4x-y+4x+y) = -2y*8x = -16xy=-16*9/8*(-0,2) =
=18*0,2 =3,6.
или
(4x -y)² -(4x+y)² =(4x)² -2*(4x)*y +y²) -(16x² +8xy+y²) =16x² -8xy+y²-16x² -8xy-y²=
-16xy
3)( 2x-5)² - 2(7x-1)² =((2x)² -2*2x*5 +5²) - 2((7x)² -2*7x*1 +1²)=
4x² -20x+25 -2(49x² -14x ²+1)= 4x² -20x +25 -98x²+28x -2 =-94x²+8x+23.
√7а-√28а+√252а=√7а(1-√4+√36)=√7а(1-2+6)=5√7а
q=1,2/0,4=3 значит b3=1,2*3=3,6 b4=3,6*3=10,8 b5=10,8*3=34,4