10.5x + 3y = 811.5
x + y = 97
y = 97 - x
3y = 291 - 3x
7.5x + 291 = 811.5
7.5x = 811.5 - 291
x = 520.5 / 7.5
x = 69.4
69 were sold at the original price
Answer:
Step-by-step explanation:
step 1
Find the slope
The formula to calculate the slope between two points is equal to
we have
(2,-1) and (-4,5)
substitute the values
step 2
Find the equation of the line in point slope form
we have
substitute
step 3
Convert to slope intercept form
isolate the variable y
102x3=306
just multiply it