Greatest common factor in this case is 2s^2. The resulting polynomial would be 2s^2(s^2-2)
Let's factorise it :

![\: {\qquad \dashrightarrow \sf {x}^{3} (x + 3) + [-5(x + 3)] }](https://tex.z-dn.net/?f=%5C%3A%20%7B%5Cqquad%20%20%5Cdashrightarrow%20%5Csf%20%20%20%20%7Bx%7D%5E%7B3%7D%20%28x%20%2B%203%29%20%2B%20%5B-5%28x%20%2B%203%29%5D%20%20%7D)
Using Distributive property we get :



⠀
Therefore,

I hope it helps you get it right
Two parallel lines never intersect, therefore they will never have a solution.
One line could be x=6 and the other could be x=2
Hope this helps :)
Let the total no. of 25 p coins be x
50p coins = 2x
Value of 25 p coins ( in rupees) = 0.25*x =0.25x
Value of 50p coins ( in rupees) = 0.5*2x = x
0.25x+x = 25
1.25x =25
x = 25/1.25 = 20
no. if 25p coins = 20
and 50p coins = 2*20 = 40