Answer:
Option B is the true statement.
Step-by-step explanation:
The given quadratic equation is y = (-6x² + 100x - 180)
In this equation y represents the daily profit and x represents the selling price.
Now we will check every option given.
A. If the selling price per ball is $5 then profit will be
y = -6×25 + 100×5 - 180 = -150 + 500 - 180 = $170
Which never defines the number of balls sold, so option A. is not correct.
B. If the selling price is $8 then profit will be
y = -6×64 + 800 - 180 = -384 + 800 - 180 = $236
This option is correct.
C. This option is not valid because we can't use number of balls to find the profit.
D. This statement is also not correct as we can see if selling price of a ball is $5 then profit is $170 and when selling price is $12 then profit is $156.
Therefore this option is also not correct.
Option B is the answer.
Answer:
The solution of y² - 1 = 15 is +4 and -4
Step-by-step explanation:
Given
y² - 1 = 15
Our solution goes thus;
Make y² the subject of formula
y² = 15 + 1
Add 15 to 1
y² = 16
Take square roots of both sides
√y² = √16
y = √16
Note that the square root of 16 is either +4 or -4 because +4 * +4 = 16 and -4 * -4 = 16; So, we replace √16 with ±4 which means + or -4
y = ±4
y = +4 and -4
Hence, the solution of y² - 1 = 15 is +4 and -4
