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A circle with centre C has equation x^2 + y^2 +8x -12y = 12

Recognise that the form this question is a circleRemember alternate circle equation (x + a)² + (x + b)² = r²Where centre of circle (-a,-b) and r is the radiusTo get the ri...

Answered by Monique G. • Maths tutor

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The perimeter of a right-angled triangle is 72 cm. The lengths of its sides are in the ratio 3 : 4 : 5 Work out the area of the triangle.

3+4+5=12,72/12=6,3x6=18, 4x6=24,Area=1/2 x 18 x 24=216

Answered by Kamil Z. • Maths tutor

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Make x the subject of the formula 3(2x – y) = ax – 4

Making x the subject of the formula means putting it into the form x = ..... As we can see there is an x on either side of the equation and brackets on the left side. Firstly according to BIDMAS we should...

Answered by Joseph Q. • Maths tutor

3641 Views

Aditi, Becky and Cali collect coins. Aditi has 6 more coins than Becky. Cali has 1 less coin than Aditi. Altogether they have 71 coins. How many coins do they each have? Show all your working.

Form 3 equations. Equation 1: A= 6+ B.Equation 2 : C= A-1. Equation 3: A+ B+ C= 71.Substitute equation 1 and 2 into 3 to get: 6+ B + B + A - 1= 71 -> 2B + A= 66 which is equation 4. Then, substitute eq...

Answered by Kelvin S. • Maths tutor

6494 Views

Differentiate the equation y = (2x+5)^2 using the chain rule to determine the x coordinate of a stationary point on the curve.

Use the chain rule as this is a composite function. Let u=2x+5.So the original equation becomes y=(u)^2.Using the chain rule: dy/dx = dy/du * du/dxdy/du = 2udu/dx = 2So dy/dx= 4uSince u=2x+5, dy/dx = 4(2x...

Answered by Daniel P. • Maths tutor

4639 Views