+0

area of paper

0
570
5

In question 9 the answer is a >> right ! ? Aug 5, 2014

#5
+10

You have just found the area of the middle bit

( 10-2x )^2

Look at my diagram and see if you can see this.  Aug 5, 2014

#1
+10

\$\$\\It\; is\; 100-4x^2\\\\
\mbox {But this is not one of the answers so we need to look some more}\\
100=10^2\\
4x^2=(2x)^2\\
\mbox{So we have a difference of two squares}\\
100-4x^2=(10-2x)(10+2x)\\

.
Aug 5, 2014
#2
0

why it 100 - 4x^2

Aug 5, 2014
#3
+10

Because you had a square peice of paper 10cm * 10cm.  That was 100cm^2

then you cut a square out of each of the 4 corners that was [xcm * xcm]*4 = 4x^2 cm^2

so you were left with  [100-4x2] cm2  of paper You need to give this question a title please.

Aug 5, 2014
#4
0

i think by this way

we have a square piece of paper with side-length 10 cm

if we cut a small square from each corner the side lenght will be 10-2X ..... then the remaining area will be ( 10-2x )^2

what is the mistake in my way ?

Aug 5, 2014
#5
+10

Look at my diagram and see if you can see this.  