Answer:
d=5
Step-by-step explanation:
The answer is the third one.
The way I think through these problems is that where you multiply (-7x), you use addition, and where you use addition (-4), you multiply.
The answers added together will equal the second number, -7, and multiplied will give you the third, -4.
What you had chosen as the answer was close. But 7.53+-0.53 equals positive 7, not negative. However they do round to -4 when multiplied.
The correct answer, -7.53 and 0.53, do equal -7 when added together and equal -4 when multiplied.
4, 7 and 9 are mutually coprime, so you can use the Chinese remainder theorem.
Start with
Taken mod 4, the last two terms vanish and we're left with
We have 
, so we can multiply the first term by 3 to guarantee that we end up with 1 mod 4.
Taken mod 7, the first and last terms vanish and we're left with
which is what we want, so no adjustments needed here.
Taken mod 9, the first two terms vanish and we're left with
so we don't need to make any adjustments here, and we end up with 
.
By the Chinese remainder theorem, we find that any 
such that
is a solution to this system, i.e. 
for any integer 
, the smallest and positive of which is 149.
Answer:
x = 77.8 ft
General Formulas and Concepts:
<u>Pre-Algebra</u>
- Order of Operations: BPEMDAS
<u>Trigonometry</u>
- sin∅ = opposite over hypotenuse
Step-by-step explanation:
<u>Step 1: Define</u>
∅ = 40°
opposite leg of angle = 50 ft
hypotenuse = x ft
<u>Step 2: Solve for </u><em><u>x</u></em>
- Substitute: sin40° = 50/x
- Multiply <em>x </em>on both sides: xsin40° = 50
- Divide sin40° on both sides: x = 50/sin40°
- Evaluate: x = 77.7862
- Round: x = 77.8 ft
