Top answers

A circle has the equation x^2 + y^2 - 4x + 10y - 115 = 0. Express the equation in the form (x - a)^2 + (y - b)^2 = k, and find the centre and radius of the circle.

Rearrange the equation so that the x terms and y terms bracketed together, like so: (x^2 - 4x) + (y^2 + 10y) - 115 = 0. Complete the square on both sets of brackets, giving (x - 2)^2 - 4 + (y + 5)^2 - 25 - 1...
JB
Answered by Joseph B. • Maths tutor
4557 Views

When do I use the preterite and when do I use the imperfect?

If you imagine a timeline (would draw out a line on the whiteboard here), the imperfect appears at some extended period over this. It is important to remember that the imperfect encompasses the ideas: someth...
PS
Answered by Paddy S. • Spanish tutor
2512 Views

How do I include quotations in essays?

There are several ways of including quotations in essays. I believe the best way is to use lots of quotations and ensure that they are embedded in your answer as to keep the argument smooth. Here is a good e...
PS
4298 Views

How do I answer a questions that begin with "To what extent"?

With "to what extent" questions, you are being asked to choose which factor is the most important in a given event or outcome. For example - let's say your question is asking, "To what extent ...
RH
Answered by Rahma H. • History tutor
9981 Views

Describe the structure of a triacylglyceride

Triacylglycerides are a type of lipid composed of a glycerol head and three fatty acid tails. The fatty acid tails are long hydrocarbon chains which are non polar and so hydrophobic, and this is what causes ...
CK
Answered by Christian K. • Biology tutor
5365 Views