Lets be a price of the calculator - $ a
then , after using the coupon, you need to pay $(a-18)
and after using 15% discount , you need to pay (1-0.15)a=0.85a
then, if
(a-18) will be more than 0.85a, you should prefer 0.15 % discount, because it will be cheaper,
a-18> 0.85a
a-0.85a>18
0.15a > 18
a>120, that means that if the price of the calculator more than $120, 15% discount is better,
but if the price of the calculator is less than $120, you should choose $ 18 coupon.
for example, we have the price of the calculator $100
100-18=82,
100*0.85 =85, coupon is better.
If the price of the calculator $200
200-18=182,
200*0.85=170, so 15% discount is better
if price of the calculator is $120,
120-18=102
120*0.85=102,
it will not matter, what you are going to use, because you are going to pay the same amount of money
Acc. to midpoint theorem,
15={(2x+9) + (4x-15)}/2
⇒ 30=2x+9+4x-15
⇒ 30-9+15=6x
⇒ 36/6=x
⇒6=x
WZ= 4x-15
=4*6-15
=24-15=9
The answer is d :) have a good day
Write out the slope formula:
m = (change in y) / (change in x)
Here,
m = n-(-9) / (-6-(-2)) = (n+9 / (-4)
Now set this slope equal to -1 and solve the resulting equation for n:
(n+9) / (-4) = - 1, or (n+9) / 4 = 1, or n+9 = 4. Then n = -5.