<span>There are different methods of subtraction. Break up the sum into different parts. 20 - 7 is 13. 0.39 - 0.60 requires borrowing 1 unit from the 13 to make 1.39 - 0.60. This makes 0.79. Add the two results together: 12 + 0.79 = 12.79.</span>
Hello :
<span>cot (2 θ) + cot ( θ) = 0
</span>cot (2 θ) = - cot ( θ)
cot (2 θ) = cot ( - θ)
2 θ = - θ +2k <span>π k in : Z
</span>θ = 2k π /3
in : <span>[0, 2π)
</span>k=0 : θ = 0
k=1 : θ = 2π /3
k=2 : θ = 4π /3

There's no solution in the set of real numbers.
Answer:
Step-by-step explanation:

To evaluate this expression, we simply plug the value of the variable into the expression and solve.
Since m = -4, plug a -4 in for m every time the m appears in the expression.
So we have (-4)^2 + 6(-4) + 3.
Start by simplifying the exponent.
(-4)^2 is 16.
Now multiply.
A positive times a negative is a negative.
So 6(-4) is -24.
So we have 16 + 24 + 3 which is 43.