Dizziness, Nonvertigo. (Nonvertigo Dizziness). ... Definition. Dizziness may cause you to feel light-headed or weak. You may feel like you are going to faint. Dizziness can happen for a short period of time or be a long-lasting condition that gets in the way of your daily activities. ... Dizziness www.lifescript.com/health/a-z/mayo/d/dizziness.aspx. Dizziness.
This is the normal case, as in our example where the equation 2 x + 3 = 7 had exactly one solution, namely x = 2. The other two cases, no solution and an infinite number of solutions, are the oddball cases that you don t expect to run into very often.
Your equation is $x+y+z+w=(x+y)+(z+w)=15$. First we see $x+y$ and $z+w$ as two unknowns, that is $a+b=15$ and $a,b$ satisfy $2\leq a,b\leq13$. Easily, we can say that there are $12$ positive integer solutions for $a$ and $b$. Then we will see there are how many postive integer solutions for $x+y=a$ and $w+z=b$.We note the number of such solutions as $N(\cdot)$. If $a=2$, then $b=13$. We see that $a=2=x+y$ has unique $1$ solutions for $x$ and $y$, that is $x=1$ and $y=1$.$b=13=z+w$ has $12$ solutions for $z$ and $w$, that is $z=1,2,\dots,12$ and $w=12,11,\dots,1$. Then there are $N(a=2)*N(b=13)=1*12=12$ solutions for $a=2$ and $b=13$.e see that $a=2=x+y$ has unique $1$ solutions for $x$ and $y$, that is $x=1$ and $y=1$. $b=13=z+w$ has $12$ solutions for $z$ and $w$, that is $z=1,2,\dots,12$ and $w=12,11,\dots,1$. Then there are $N(a=2)*N(b=13)=1*12=12$ solutions for $a=2$ and $b=13$.