The first box is 3 more than the quotient of 6 and a number, the second is 6 less than the product of 3 and a number, the third box is the product of 6 and the sum of a number and 3.
You can make a start by putting together an expression for the sum of the even integers between 1 and k inclusive.
Let S be the sum of the even integers between 1 and k inclusive.
Then:
<span><span>S=2+4+6+⋯+(k−2)+k</span></span>
As k is even, you can say r = 2k and so:
<span><span>S=2(1+2+3+⋯+(r−1)+r)</span></span>
<span>Now the sum of the first </span><span>r</span><span> numbers is well-known, it's the </span><span>r</span>th triangle number and we have:
<span><span>1+2+3+⋯+(r−1)+r=<span><span>r(r+1)/</span>2</span></span></span>
<span>Now we can keep it simple and say </span><span><span>2k=4r </span></span><span>and so:</span>
<span><span>S=2(1+2+3+⋯+(r−1)+r)=4r=2<span><span>r(r+1)</span>2</span>=r(r+1)</span></span>
<span>So you can build a quadratic in </span><span>r</span><span> and so get </span><span>k.</span>
If you look closely you'll see that x can take on any real value here. On the other hand, y can equal -4 (maximum) or any real number smaller than -4.
Translate this information into interval notation.
For example
f(x)=3x+2 and f(x)=x/x-1
