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What is the difference between 'ser' and 'estar'?

The verbs 'ser' and 'estar' both translate to the English 'to be'. But don't worry! There are some key differences that help us know which Spanish verb we should use. 'Ser' is used to describe permanent c...

Answered by Leah G. • Spanish tutor

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FP1 June 2016 Edexcel Exam Paper Question 7

Question7. A complex number z is given by z = a + 2i where a is a non-zero real number. (a) Find z2 + 2z in the form x + iy where x and y are real expressions in terms of a. (4) Given that z2 + 2z is real...

Answered by Josephine R. • Further Mathematics tutor

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Briefly describe the terms "antigen" and "antibody", and describe the structure of the latter. Briefly describe the processes of opsonisation, phagocytosis and destruction of bacteria by macrophages.

An “antigen” is a specific foreign molecular entity which is bound by antibodies during an immune response. Examples of antigens include peptides from bacterial surface proteins, which signal the presence...

Answered by Andrew R. • Biology tutor

2247 Views

a)By completing the square, prove the quadratic formula starting from ax^2+bx+c=0, b) hence, or otherwise solve 3x^2 + 7x -2= 9, to 3s.f.

a)starting from ax²+bx+c=0, divide through by a, x²+(b/a)x+c/a=0, complete the square (x+(b/2a))²-(b/2a)² +c/a=0, expand (x+(b/2a))²-(b²/4...

Answered by Yusuf H. • Maths tutor

3223 Views

In an experiment a burrette was identified as the largest source of uncertainty, how could this uncertainty be reduced?

A burrette is a measuring apparatus a burrette measures the volume of liquid delivered during a titration. with each measurement there is an uncertainty with the recorded measurement of delivered liquid. ...

Answered by Jarrod G. • Chemistry tutor

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