Answer:
- 39 quarters and 41 nickels
Step-by-step explanation:
Let the number of quarters be x and nickels be y.
<u>Given:</u>
- Quarter is 25 cents
- Nickel is 5 cents
- Number of coins is 80
- Total amount is $11.80 = 1180 cents
<u>We have equations:</u>
- x + y = 80
- 25x + 5y = 1180
<u>Solve the system by elimination, subtract 5 times the first equation from the second one:</u>
- 25x + 5y - 5x - 5y = 1180 - 80*5
- 20x = 780
- x = 780/20
- x = 39
<u>Find the value of y:</u>
- 39 + y = 80
- y = 80 - 39y = 41
<u>Verify:</u>
- 25*39 + 5*41 = 975 + 205 = 1180
w-(-3)=7
Pretend that there is a -1 in front of the bracket
w-1(-3)=7
Mutiply the bracket by -1
(-1)(-3)=3
w+3=7
Move +3 to the other side. Sign changes from +3 to -3.
w+3-3=7-3
w=4
Answer: w=4
Answer:
- -6x² - 6 = -7x - 9
- -6x² + 7x - 6 + 9 = 0
- -6x² + 7x + 3 = 0
- 6x² - 7x - 3 = 0
<u>Discriminant:</u>
- D = (-7)² - 4*6*(-3) = 49 + 72 = 121
<u>Since D > 0, there are 2 real solutions:</u>
- x = (- (-7) ±√121 )/12
- x = (7 ± 11)/12
- x = 1.5, x = -1/3
Rotation of a point through 90-degree is about he origin in clockwise direction when point M(h,k) is rotated about the origin O through 90-degree in clockwise direction
