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It is given that z = 3i(7-i)(i+1). Show that z can be written in the form 24i - k. State the integer k.

z = 3i(7-i)(i+1)= 3i(7i-i+7-i 2 )= 3i(6i+8)= 18i 2 +24 (1 method mark)= 24i-18 (1 method mark)k=18 (1 answer mark)
DT
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What are surds and how do I use them ?

Surds are irrational numbers, (numbers which cannot be expressed as fractions), and normally shown as a number instead a square root, but the number itself isn't a square. For example root 3 is a surd, while...
RH
Answered by Roly H. • Maths tutor
7254 Views

Astronauts on the ISS orbit Earth 16 times a day at a height of 400km above the surface. Given that the radius of Earth is approximately 6400km, how fast are the astronauts travelling?

v = 2𝜋R/T where R is the orbital radius, T is the time period.R = radius_of_earth + height_of_orbit = 6800km + 400km = 6800km = 6.8×10 6 m.T = hours_in_day/number_of_orbits_in_day = 24/16 hours = 1.5 hours =...
PV
Answered by Paaryn V. • Physics tutor
3120 Views

What is the function of the cell membrane?

It controls what enters and leaves the cell.
YA
Answered by Yemi A. • Biology tutor
2903 Views

Explain trend in why the ionisation energies increase across the period

As we travel along the period the nuclear charge increases, this increases the grip the nuclei of the atom has on the electrons. As they are on the same period they experience almost the exactly the same ele...
PJ
Answered by Patrick J. • Chemistry tutor
2271 Views