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Solve the simultaneous equations: y=3x+2, x^2+y^2=20

y=3x+2 x^2+y^2=20 x^2+(3x+2)^2=20 x^2+(3x+2)(3x+2)=20 x^2+(9x^2+6x+6x+4)=20 x^2+(9x^2+12x+4)=20 10x^2+12x+4=20 10x^2+12x-16=0 5x^2+6x-8=0 (5x-4)(x+2)=0 5x-4=0, x+2=0 x=4/5=0.8, x=-2 y=3x+2, y=3x+2 y=3(0.8)+2...
DC
Answered by Daniela C. • Maths tutor
16101 Views

If a student uses an electric kettle connected to a 230V mains power supply, with a heating power of 1.8kW. Assuming negligable losses, answer the following: a) find the current in the kettle b) find the total energy transferred in 2 minutes of operation

a) The governing equation here is Power = current x voltage or P=IV. using this formula, 1,800 = I x 230 => I=1800/230 = 7.83 A (3sf) b) as watts is equal to joules/seconds, we can find the energy in joul...
CP
Answered by Chris P. • Physics tutor
22189 Views

3x^2 + 7x - 13 = 0. What is x?

By using the quadratic quation, it can be deduced that x = 1.22 or x = -3.55
MS
Answered by Miranda S. • Maths tutor
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Simplify the surd sqrt(48)

When simplifying surd expressions we want to look for square numbers that are factors of the number inside the square root. If we list the square numbers (which are numbers that are the result of squaring an...
MH
Answered by Matthew H. • Maths tutor
42194 Views

Rationalise the denominator and simplify: 10/3√5 (2 marks)

First of all, you need to read the question really carefully and look at how many marks it is worth. The question is worth two marks and it is asking you to do two things: firstly, you need to ‘rationalise t...
MP
Answered by Megan P. • Maths tutor
16737 Views