It's a reflection over the y axis because 'a' represents 'x' and if 'a' is negative it flips to the other side leave 'b/y' to remain the same
Answer: the length is 11 cm.
The width is 7 cm.
Step-by-step explanation:
Let L represent the length of the rectangular plastic box.
Let W represent the width of the rectangular plastic box.
The area of the rectangular top of the box is 77 square cm. This means that
LW = 77- - - - - - - ;- - - -1
The plastic box has a length 4 cm longer than its width. This means that
L = W + 4
Substituting L = W + 4 into equation 1, it becomes
(W + 4)W = 77
W² + 4W = 77
W² + 4W - 77 = 0
W² + 11W - 7W - 77 = 0
W(W + 11) - 7(W + 11) = 0
W - 7 = 0 or W + 11 = 0
W = 7 or W = - 11
Since the width cannot be negative, then W = 7cm
L = 77/7 = 11 cm
Sum/difference:
Let

This means that

Now, assume that
is rational. The sum/difference of two rational numbers is still rational (so 5-x is rational), and the division by 3 doesn't change this. So, you have that the square root of 8 equals a rational number, which is false. The mistake must have been supposing that
was rational, which proves that the sum/difference of the two given terms was irrational
Multiplication/division:
The logic is actually the same: if we multiply the two terms we get

if again we assume x to be rational, we have

But if x is rational, so is -x/15, and again we come to a contradiction: we have the square root of 8 on one side, which is irrational, and -x/15 on the other, which is rational. So, again, x must have been irrational. You can prove the same claim for the division in a totally similar fashion.
Hey there! I'm happy to help!
Let's say that we don't have jokers. In that case, there are 52 cards, and half of them are red (so 26 are red). The probability of pulling a red card once is 1/2 since half the cards are red.
If we pick one out, there are only 51 total cards left and 25 red cards. So, the probability of picking one again would be 25/51.
We multiply the probabilities of these two events to find the probability of them both happening.
1/2×25/51=25/102
The probability of picking two red cards in a row is 25/102 or around 24.5%.
Have a wonderful day! :D
The difference between 90% and 72% is 18%