Answer:
First image attached
The error was done in Step E, because student did not multiply
by the negative sign in numerator. Step E must be
.
Second image attached
The error was done in Step C, because the student omitted the
of the algebraic identity
. Step C must be 
Step-by-step explanation:
First image attached
The error was done in Step E, because student did not multiply
by the negative sign in numerator. The real numerator in Step E should be:

Hence, Step E must be
.
Second image attached
The error was done in Step C, because the student omitted the
of the algebraic identity
. Step C must be 
And further steps are described below:
Step D

Which according to the Quadratic Formula, represents a polynomial with complex roots. That is: (
,
,
)


(Conjugated complex roots)
Step E

Step F

To figure this out you first need to determine how many kg there are in 220 lbs. 1 lb equals 0.454 kg, so 220 lbs= 99.88 kg.
It states that a patient receives 7mcg per kg per minute, so the patient will receive 7 x 99.88=699.16 mcg per minute.
You need to convert this to a number of mcg per hour, so multiply the amount by 60 to get 41949.6 mcg per hour.

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Write the divide fraction horizontally:
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Factorise the numerators and denominators when possible:
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Convert the divide fraction to multiplication fraction
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Cancel the factors
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Combine to single fraction
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Angle UTV is basically given: it's 138°.
Moreover, since UTV is isosceles, the other two angles have the same measure x. We thus have

So, TUV is 21°, and VUW is complementary, so it must be 69° so that they sum up to 90°