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Show x^2 + 8x +15 = 0 in the form of (x+b)^2 +c (complete the square) and then solve the equation

x 2 +8x +15 = 0 (x+4) 2 -16 +15=0 (x+4) 2 -1=0 (x+4)= (+/-)1 x = -3 or -5
OA
Answered by Omar A. • Maths tutor
4287 Views

How do I work out the area of a quarter circle with radius 6cm?

The easiest way to do this is to first work out the area of the whole circle. To work out the area of a circle, the equation is area = πr 2 , where r is the radius. So, to work out the area we work out π x 6...
CC
Answered by Carla C. • Maths tutor
14193 Views

The line PQ is the diameter of a circle, where points P and Q have the coordinates (4,7) and (-8,3) respectively. Find the equation of the circle.

Start by using the formula d = sqrt((x 2 -x 1 ) 2 +(y 2 -y 1 ) 2 )Therefore, substituting in our coordinates from P and Q:Length PQ = sqrt((-8-4) 2 +(3-7) 2 )= sqrt((-12) 2 +(-4) 2 )= sqrt(160)= sqrt(16) x s...
MC
Answered by Matt C. • Maths tutor
11317 Views

Prove that 2cot2x+tanx=cotx

2cot2x= 2(1/tan2x)= 2(1/(2tanx/1-tan 2 x))=2(1-tan 2 x)/2tanx= (1-tan 2 x)/tanx(1-tan 2 x)/tanx +tanx=(1-tan 2 x)/tanx +tan 2 x/tanx=1/tanx=cotx
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Answered by Alisa D. • Maths tutor
21610 Views

Write x^2-4x+9 in the form (x-p)^2+q, where p and q are integers.

To complete this task we use a method called "Completing the square. For this we use a formula (a+b)^2=a^2+2ab+b^2. Now we see that in the example we have a term x^2 so we put x^2=a^2 so we can have tha...
MS
Answered by Maria S. • Maths tutor
6738 Views