Answer:
x ≈ 1.32, x ≈ - 5.32
Step-by-step explanation:
Given
x² + 4x - 7 = 0 ( add 7 to both sides )
x² + 4x = 7
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 7 + 4
(x + 2)² = 11 ( take the square root of both sides )
x + 2 = ± 
( subtract 2 from both sides )
x = - 2 ± 
Thus
x = - 2 - ≈ - 5.32 ( to 2 dec. places )
x = - 2 + ≈ 1.32 ( to 2 dec. places )
Answer: 8 textbooks
Step-by-step explanation:
Sold 40 notebooks = 40 x $4 = $160
$800 - $160 = $640 left to sell
$640/$80 (cost of textbook) = 8 textbooks need to be sold
Answer: He jogs 12 miles per hour
Step-by-step explanation: Every 15 minutes he jogs 3 miles, there are 60 minutes in an hour, 60/15 = 4, 4 x 3 = 12
Answer:
Step-by-step explanation:
Charges up to 20 passengers = $540 per person per day
Total charges = 540 × 20 = $10800
If x passengers above 20 sign up for the cruise then total number of passengers = (20 + x)
Total revenue = $(20+x)
But each fare is reduced by $7 for additional passenger above 20 then revenue generated R(x) = 540(20+x) - 7x
R(x) = 10800 + 540x - 7x
R(x) = 10800 + 533x
a). Revenue per day realized R = 10800 + 533x
b). R(48) = 10800 + 48×533
= $36,384
C). R(78) = 10800 + 78×543
= $53,154
