Answer:
It has a negative slope = -2
Step-by-step explanation:
Let y be the price and x be the quantity purchased . Then putting the value of x in the equation we can find the price= y
where  y = −2x+8
x    0    1     2     3     4     5     6     7
y    8    6     4     2     0     -2     -4    -6
So we can plot the demand curve which has a negative slope.
We see from the values above that the slope is negative having a value equal to -2. This means that for every increase in the number of quantities there is a decrease in the price.