Answer:
x = 13
Step-by-step explanation:
x = hypotenuse which is c in the Pythagorean theorem
c = √a^2 + b^2
c = √12^2 + 5^2
c = 13
Answer: 
Step-by-step explanation:
We apply the formula
.
Note that
. Take
and
in the formula above to get

Then the value of this expression is 
We can use the cosine addition formula again to simplify further. Decompose the fraction in the argument as:

Applying the formula with
and
we obtain

We conclude that this expression has the value 
Simplify both sides of the equation. (Distribute)
<span><span><span><span>(−7.8)</span>(x)</span>+<span><span>(−7.8)</span>(6.5)</span></span>=−25.74 </span> <span><span><span><span>−7.8x </span>+ </span>−50.7</span>= −25.74 -------------> </span>−7.8x − 50.7= −25.74
<span>Add 50.7 to both sides.
</span><span><span><span>−7.8x </span>− 50.7 </span>+ 50.7 </span>= <span>−25.74 + 50.7 ---------------------> </span><span>−7.8x </span>= <span>24.96
</span><span>Divide both sides by -7.8.
</span><span><span>−7.8x /</span>−7.8 </span>= <span>24.96/<span>−<span>7.8
</span></span></span><span>
X= </span><span>−3.2 :D</span><span>
</span>