A) Sum numbers, divide by 5
B) Use standard deviation formula
I assume it is saying a has 3 factors and b is a factor of a+4?
Note that the condition implies $a$ is a square of a prime, which must be b.
Point:=$(a,b)$. Then $b=13\pm 5$.
If $b=18$: $(a,18)\to (7,15)=18$. So $(a-7)^2=18^2-9$. Finish from here
If $b=8$: Same thing
$6\cos Q=6\cos(90-R)=6\sin R=tan R\implies 6=\frac{1}{\cos R}\implies \cos R=6$.
The end is near
Simply use the equations $x=r\cos\theta, y=r\sin\theta$ upon dividing both sides by $r$.
Not sure, on my end it seems like "Guest".
The other answer isn't insightful whatsoever.
Note RHS = $\frac{8}{15}$ and LHS = $\frac{j+k}{jk}$. So $15j+15k=8jk$. Now use simons favorite factoring trick.
By distance formula, $(2a-4)^2+(a-5)^2=(2\sqrt{30})^2$. Solve for $a$ via quadratic methods.
For obvious reasons, $(0,0)\to (m,n)$ can be done in $\binom{m+n}{m}=\binom{m+n}{n}$ ways. We let $f(m,n):=(0,0)\to (m,n)$.
So we just want $f(5,7)-f(4,3)f(5-4, 7-3)$, which is trivial to compute using the expression for $f(m,n)$.
Note that by synthetic division $-3 x^2 + 12 x + 22 = (-3 x - 3)(x - 5) + 7 = -3(x+1)(x-5)+7$. Divide both sides by $x-5$.
