Answer:

Step-by-step explanation:
we have the expression:

We need to multiply the two terms in the first parenthesis by the two terms in the second parenthesis:

we solve each term taking into account the law of signs
(-)(-)=+
and
(+)(-)=-
also for the first term we use that 
thus we have:

it can be simplified a little more if we factor an r of the second and third term:

OFFER A is cheaper.
Step-by-step explanation:
Given,
OFFER A
Pack of 5
£2.75
Pay for 3 packs get 1 free
And
OFFER A
Pack of 5
£2.75
Pay for 3 packs get 1 free
To find which offer is cheaper.
<u>For OFFER A</u>
For 4 Packets he needs to pay £2.75
He needs to buy 40 batteries.
He needs to buy 40÷(4×5) = 2 packets.
Total cost = £2.75
×2 = £5.5
<u>For OFFER B</u>
For 4 Packets he needs to pay £2.52
He needs to buy 40 batteries.
He needs to buy 10 packets.
After discount he has to pay = £2.52
-(£2.52
×
) = £1.68
Total cost = £1.68×10 = £16.8
Hence,
OFFER A is cheaper.
X equals 4 because 2 times 2 equals 4 and then 4 times 4 =16