If 8x300=2,400, then 8x320 would equal 2,560. Why? Because 8x20=160. 2,400+160=2,560.
Hope this helps! :)
Hey there!!
How do we find slopes ?
Slope = 
We are given with two co-ordinates :
(-1,8) and (3,-4)
Hence, the slope is :

...
= -3
The slope is -3.
Hope my answer helps!
The original price was £320 before the 40% sale price
<B+<D = 180
x+148 = 180
x = 32
<A = 2(32) + 1
<A = 64+1
<A = 65