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Solve the simultaneous equations: 6x + 3y = 42 4x + 7y = 38

6x + 3y = 42 => y = 14 - 2x (1 method mark)4x + 7y = 38 (substituting in y) => (1 method mark) 4x + 7(14 - 2x) = 384x + 98 - 14x = 38-10x + 98 = 3860 = 10x => x = 6 (1 answer mark) => y = 14 -...

Answered by Daniel T. • Maths tutor

3952 Views

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-i²)= 3i(6i+8)= 18i²+24 (1 method mark)= 24i-18 (1 method mark)k=18 (1 answer mark)

Answered by Daniel T. • Further Mathematics tutor

2467 Views

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, wh...

Answered by Roly H. • Maths tutor

6974 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 = 6.8×10⁶m.T = hours_in_day/number_of_orbits_in_day = 24/16 hours =...

Answered by Paaryn V. • Physics tutor

2791 Views