x 12
the 12 in the numerator (top) and the 12 in the denominator (bottom) cross out so you are left with 50.
Answer: 50
Step-by-step explanation:
1. No: angles add to more than 180 deg.
2. Yes: each side's length is between the sum and difference of the lengths of the other two sides.
3. No: not every side's length is between the sum and difference of the lengths of the other two sides.
4. Yes: for example, place the 50 deg angle between the two given sides. Another side will then make the triangle.
5. Yes: for example, use 3 cm as the short leg in a 30-60-90 right triangle.
Answer:
Second choice:


Fifth choice:


Step-by-step explanation:
Let's look at choice 1.


I'm going to subtract 1 on both sides for the first equation giving me
. I will replace the
in the second equation with this substitution from equation 1.

Expand using the distributive property and the identity
:




So this not the desired result.
Let's look at choice 2.


Solve the first equation for
by dividing both sides by 2:
.
Let's plug this into equation 2:



This is the desired result.
Choice 3:


Solve the first equation for
by adding 3 on both sides:
.
Plug into second equation:

Expanding using the distributive property and the earlier identity mentioned to expand the binomial square:



Not the desired result.
Choice 4:


I'm going to solve the bottom equation for
since I don't want to deal with square roots.
Add 3 on both sides:

Divide both sides by 2:

Plug into equation 1:

This is not the desired result because the
variable will be squared now instead of the
variable.
Choice 5:


Solve the first equation for
by subtracting 1 on both sides:
.
Plug into equation 2:

Distribute and use the binomial square identity used earlier:



.
This is the desired result.