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Complete the square of the following expression: 2x^2 -8x+21

2(x-2)^2 +13
IF
Answered by Iliya F. • Maths tutor
4118 Views

A point lies on a circles diameter such that the distance from the point to the edge of circle is 4 times the distance from the point to the centre. What is the circles area in cm^2 if the distance from the point to edge is 5cm?

first we know that the length given has a 4:1 ratio with the remaining length of the radius so 5/4 + 5 = 25/4 = radius, the formula for the area of a circle is A=pi*(r^2) so the area is 625/16*pi.
LR
Answered by Luka R. • Maths tutor
3085 Views

What are the possible ways to find the roots from a quadratic equation?

quadratic equation where the coefficients of the quadratic equation: ax^2 + bx + c are substituted into the formula: [-b +- (b^2 - 4ac)^0.5] / 2a. The roots are what x equalscompleting the square where the c...
SB
Answered by Sophie B. • Maths tutor
3762 Views

Factorise and Solve x^2 + 10x + 15 = -6

To factorise an equation like this we must first make the equation equal to 0 therefore it becomes: x^2+10x+21.Now we have the equation in a way that we can work with it we can factorise.To do this we need t...
JV
Answered by Joseph V. • Maths tutor
3676 Views

Yesterday it took 5 cleaners 4 and ½ hours to clean all the rooms in a hotel. There are only 3 cleaners to clean all the rooms in the hotel today. How much time will it take them?

Firstly we need to identify what is the underlying principle of this question and what are the assumptions we have to make. We are given some information about the cleaning process in a hotel. The variables ...
VV
Answered by Viola V. • Maths tutor
13287 Views