Answer:

Step-by-step explanation:
Given:
The above triangle
Required
Solve for AB in terms of a, b and angle C
Considering right angled triangle BOC where O is the point between b-x and x
From BOC, we have that:

Make h the subject:

Also, in BOC (Using Pythagoras)

Make
the subject

Substitute
for h
becomes


Factorize

In trigonometry:

So, we have that:

Take square roots of both sides

In triangle BOA, applying Pythagoras theorem, we have that:

Open bracket

Substitute
and
in 


Open Bracket

Reorder

Factorize:

In trigonometry:

So, we have that:


Take square roots of both sides

Answer:

Step-by-step explanation:
Convert each to a improper fraction



80-64=24
24 is 30% of 80 so a decrease of 30%
1. 4 • (–3) • 5
so 4 x (-3) = -12 and then -12 x 5 = -60
2. (2.25 x 23) x 4
so (2.25 x 23) 51.75 and then 51.75 x4 = 207
4. 5 x 12 x (-2)
so 5 x 12 = 60 and then 60 x (-2) = -120
5. 35(26)(0) =
so 35 x 26 = 910 and then 910 x 0 = 0