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Solve x^2+4x-5=0 by completing the square.

x^2+4x-5=0(x+2)^2-(2)^2-5=0subtract 2^2 as (x+2)^2 = x^2+4x+4 when we want x^2+4x(x+2)^2-4-5=0(x+2)^2-9=0(x+2)^2=9square root both sidesx+2=+/-3x=-2+/-3x=-2+3 or x=-2-3x=1 or x=-5
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Answered by Evie M. • Maths tutor
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The radius of a pizza is 12cm, calculate the area of the pizza in terms of pi

To calculate the answer to this question we need to know the formula for the area of the circle. The area of a circle is: A = Pi x r^2 The value of r is given in the question; r = 12. We then just plug this ...
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Answered by Beth B. • Maths tutor
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GCSE 2011: Solve the simultaneous equations: y^2 = 2x + 29 and y = x - 3

This was the final question in AQA's 2011 non-calculator paper, and most top candidates will be looking to score all 5 marks that are on offer. Our usual technique for simultaneous equations isn't going to w...
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Answered by Ross G. • Maths tutor
8475 Views

The circle c has equation x^2+ y^2 = 1. The line l has gradient 3 and intercepts the y axis at the point (0, 1). c and l intersect at two points. Find the co-ordinates of these points.

x^2 + y^2 =1 y = 3x + 1 x^2 + (3x + 1)^2 = 1 x^2 + 9x^2 + 6x+ 1 = 1 10x^2 + 6x = 0 x(10x+6) = 0 x= 0 or x = -6/10 = -3/5 When x = 0, y = 1 When x = -3/5, y = -4/5
PJ
Answered by Prince J. • Maths tutor
4472 Views

How do you use SOH CAH TOA?

If you have a right angled triangle, it is made up of a hypotenuse, adjacent and opposite. In SOH CAH TOA, the middle letter goes up, so when we use the equation, it will be sin=opposite/hypotenuse, etc. If,...
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Answered by Katherine R. • Maths tutor
4918 Views