Top answers

Solve 2x^2+ 7x -8 = 0, giving your answer to 2 decimal places.

You can solve this equation using the quadratic formula: x = -b +/- root(b 2 - 4ac) 2aSo, a=2, b=7, c=-8:x = -7 +/- root(7 2 - 4 x 2 x -8) 2 x 2So, x = 0.31 or -3.81
MK
Answered by Michelle K. • Maths tutor
8622 Views

Find the exact solution, in its simplest form, to the equation ln(4y + 7) = 3 + ln(2 – y) (Core Maths 3 Style Question)

First we subtract ln(2-y) from both sides to get "ln(4y+7) - ln(2-y) = 3". By applying the laws of logs from C2, we have "ln[(4y+7)/(2-y)] = 3". Therefore, if we put them as exponents of ...
DB
Answered by Danielle B. • Maths tutor
4559 Views

Prove algebraically that 
(2n + 1)^2 – (2n + 1) is an even number for all positive integer values of n. (3 marks)

We can show something is even if it is a multiple of two, as every multiple of two is even. It is useful to see certain tricks, and I will aim to teach you these in my tutorials, these tricks make problems e...
BH
Answered by Ben H. • Maths tutor
7093 Views

Describe how phagocytosis of a virus leads to presentation of its antigens (3 marks)

Virus engulfed by phagocyte (broad immune response), destroyed using lysosomes (hydrolysis) and viral antigens presented on cell membrane (trigger specific immune response e.g. anti-bodies). Steps of phagocy...
BJ
Answered by Ben J. • Biology tutor
27888 Views

Describe the function of enzymes DNA helicase and DNA polymerase during DNA replication (2 marks)

DNA replication occurs in two phases: DNA separation (DNA helicase) and DNA transcription (DNA polymerase) Enzyme Function: 1. DNA helicase – (unwinding DNA and) breaking hydrogen bonds between DNA strands (...
BJ
Answered by Ben J. • Biology tutor
10662 Views