It's a simultaneous equation:
Steps:
1.Number the equations..
a+b=77 -1
a-b=13 -2
2. Choose what variable you want to use. In this case I would use the "b". Since the signs in front of the "b's" are different, add the two equations together
a + b = 77
+ + +
a (-b) = 13
Which gives;
2a = 90
Then solve to find a:
2a=90
a= 90/2
a=45
3.Then plug the "a" value into any of the original equations to find the "b" value. I would use equation 1 since the all the variables are positive.
a + b = 77
(45) + b = 77
b=77-45
b=32
4.Solution
a=45
b=32
An equation for the sentence would be g + 7 = 12, where g is the unknown number of gallons.
Answer:
d
Step-by-step explanation:
keep change flip
keep 6/7
change division to multiplication
flip 18/3 to 3/18
Answer: The percentage of legal quarters will be rejected by the vending machine = 2.275%
Step-by-step explanation:
Given: The weights of legal U.S. quarters have a normal distribution with a mean of 5.67 grams and a standard deviation of 0.07 gram.
Let x be the weights of legal U.S. quarters .
Required probability: 
![=P(\dfrac{x-\mu}{\sigma}\dfrac{5.81-5.67}{0.07})\\\\=P(z2)\approx0.02275 \ \ \ [By\ P-value\ calculator]](https://tex.z-dn.net/?f=%3DP%28%5Cdfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%3C%5Cdfrac%7B5.33-5.67%7D%7B0.07%7D%29%2BP%28%5Cdfrac%7Bx-%5Cmu%7D%7B%5Csigma%7D%3E%5Cdfrac%7B5.81-5.67%7D%7B0.07%7D%29%5C%5C%5C%5C%3DP%28z%3C-4.857%29%2BP%28z%3E2%29%5Capprox0.02275%20%20%20%20%5C%20%5C%20%5C%20%5BBy%5C%20%20P-value%5C%20calculator%5D)
The percentage of legal quarters will be rejected by the vending machine = 2.275%
The number of terms in the binomial expansion of (3x-5)^9 is 10
