Quadratics question, quite simple help really needed! :(?

Question

firstly heres the diagram the question refers to, its not to scale.
http://s304.photobucket.com/albums/nn167/xBeax16/?action=view¤t=NewPicture.jpg
heres the question:
In the diagram each side of the square ABCD is (3 + x)cm.
a) write down an expression in terms of x for the area, in cm^2, of the square ABCD

so ive done this part, and i put x = (3 + x)^4 is that right?

now this is the bit i dont know what to do for:
b) The actual square ABCD is 10cm^2
Show that x^2 + 6x = 1

HELP GREATFULLY RECEIVED 10PTS for good answer :) please help me if you can i beg for help! thank you
b)

Answer 1

Your close with part a. However, it is not (3 + x)^4 but (3 + x)^2



For part b we can expand the area eqaution (3 + x)^2 and set it equal to 10 cm and we get



9 + 6x + x^2 = 10



rearrange terms and we get



x^2 + 6x = 1

Answer 2

Your part a) is wrong, a common mistake.



When you have a square, the area is height x width, so since both sides are (3+x)cm, this would be:

AREA = (3 + x)^2



What you did was height x height x width x width



For part b),

Expand the brackets, which becomes:

AREA = x^2 + 3x + 3x + 9

Which, when simplified, becomes:

AREA = x^2 + 6x + 9



We know the area is 10, so you insert the 10 into the equation:

10 = x^2 + 6x + 9

(10-9) = x^2 + 6x

1 = x^2 + 6x



Equation solved.

Hope that helps!

Answer 3

Well you have a couple of small but deadly errors.

Area = (x + 3)^2



What the next part is telling you is that the area = 10cm^2

10 = (x + 3)^2 foil the right

x^2 + 3x + 3x + 9 = 10 Now subtract 9 from both sides.



x^2 + 6x = 10 - 9

x^2 + 6x = 1

Answer 4

a) x = (3 + x)^2 cm^2



b) x^2 + 6x = 1



x^2 + 6x + 9 = 10 (expanding the brackets in a)



Subtract 9 from both sides of the = sign, giving the answer you need to show how to solve.