A)8am-4ab b)m(a--a) c)49x²-25y² d)x²-4x-12 e)y²+9,7y-3

A)8am-4ab=4а(2m-b)

b)m(a-b)-(b-a)=
m(a-b)+(a-b)=
(a-b)(m+1)

c)49x²-25y²=
(7x-5y)(7x+5y)

d)x²-4x-12=
(x-6)(x+2)

D=16+48=64
x1=4+8/2=12/2=6
x2=4-8/2=-4/2=-2

e)y²+9,7y-3=
(y-0,3)(y+10)

D= 94,09+12=106,09 (10,3²)
y1=-9,7+10,3/2=0,6/2=0,3
y2=-9,7-10,3/2=-20/2=-10