<h3>
</h3><h3 /><h3><u>Question</u> : 14</h3>
let's solve for f :
Taking reciprocal of both sides :
Answer:
(x + 9)² = 36
Step-by-step explanation:
Given
x² + 18x + 57 = 12 ( subtract 57 from both sides )
x² + 18x = - 45
To complete the square
add ( half the coefficient of the x- term)² to both sides
x² + 2(9)x + 81 = - 45 + 81
(x + 9)² = 36
Answer:
B
Step-by-step explanation:
480 pennies.
25% are dated before 1980, therefore:
1200(total):100 = 12 (1%)
12(1%)x25 = 300 (25%)
35% are dated from 1980 to 2000, therefore:
12(1%)x35 = 420 (35%)
25% are dated before 1980, 35% are dated from 1980 to 2000 and the rest are dated after 2000.
25% + 35% = 60%.
300(25%) + 420(35%) = 720.
60% = 720.
100%-60% = 40%.
40% is the amount of pennies that are dated after 2000.
The total (100%) of the pennies is 1200.
We also know that 60% of the total (1200) is 720.
1200(100%) - 720(60%) = 480(40%).
Therefore, the amount of pennies dated after 2000 in Russell’s Collection is 480.