If you distribute, then you get -10x+7.5
Note how -2.5 times 4x = -10x and how -2.5 times -3 = 7.5
The idea is that you multiply the outer term (-2.5) by each term inside
You need to subtract the numbers for 180 and you will have the answer
-1/4 will be ration because all fractions are rational
I got 7.1 x 10^(-11) but it's been a few years so I could've done it wrong
see the attached figure to better understand the problem
we have that

Step 1
<u>Find the value of AC</u>
we know that
in the right triangle ABC

substitute the values in the formula

Step 2
<u>Find the value of BC</u>
we know that
in the right triangle ABC
Applying the Pythagorean Theorem

substitute the values

Step 3
<u>Find the value of BD</u>
we know that
in the right triangle BCD
Applying the Pythagorean Theorem

substitute the values


therefore
<u>the answer is</u>
the length of BD is 11.93 units