Answer:
2nd
Step-by-step explanation:
using the quadric formula

do the math and you get the second one.
{-1/3,5/2}
There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:

Now since

, then the expression becomes:
Answer:
Cody has solved (12 × 12) = 144 problems.
Step-by-step explanation:
For every one problem that Julia completes, Cody completes twelve.
If Julia Completes x problems and Cody completes y problems, then we can write y = 12x ........ (1)
Now, given that the number of problems solved by Cody is one hundred twenty more than two times the number of problems solved by Julia.
Hence, 2x + 120 = y ......... (2)
Now, from equations (1) and (2) we get,
2x + 120 = 12x
⇒ 10x = 120
⇒ x = 12
Therefore, Cody has solved (12 × 12) = 144 problems. (Answer)
Step-by-step explanation:
what do u need help solve
Answer:
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Step-by-step explanation: