Question

1) factorise 3ac-ab
2) (y-1/y)=4, find the valu of y^2+1/y^2)

Answer 1

1);-

a(3c-b),


2):-

since

y-1/y =4,

then

(y-1/y)²=y²+1/y²-2,


hence

4² =y²+1/y²-2,

16 = y²+1/y²-2,

hence

y²+1/y²=16+2=18

Answer 2

1) 3ac-ab
= a (3c-b)

2) y-1/y=4
squaring both sides
y^2 +1/y^2-2=16
y^2+1/y^2=18

hope it helps u