CPhill

 -3x^2 + 2y^2 + 5xy - 2y + 5x^2 - 3y       combine like terms

2x^2 +  2y^2  - 5y + 5xy

No prob.......!!!!

NO!!!!!!

√ (-3)  is a non-real number  while √ (3)   is real

Yep

√1.1  = 1.04881.......  and   √1.2   = 1.09545.....

Area = W * L

10⁴ = W * 10³         divide both sides by 103

10⁴ / 10³  = W  = 10

1.  √2 ≈ 1.414......      √3 = 1.732........

2. No, an irrational number cannot be written in exact decimal form. Every rational number can either be expressed as either a terminaring or a repeating decimal, but an irrational number can only be expressed as a non-repeating decimal.

72 gallons =  144 half gallons

So.....

144 / (1 / 8)   = 

144 * 8   =  

1152 cups available

1152 / [ 1 + 2/3]  =

1152 / [ 5/3]  =

1152 * 3/5  =

about 691 cakes

( x + 1 ) ! / x!   =

[ (x + 1) * x * (x - 1) * ......* 3 * 2 * 1 ]  /  [ x * (x - 1) * (x - 2)*......* 3 * 2 * 1]   =

x + 1

712 ! / 710!   =

[  712 * 711 * 710 *........*3 * 2 *1 ]  /   [ 710 * 709 * 708*......*3 * 2 * 1 ]  =

712 * 711   =

506,232

Let the equal sides of the black triangle  = x = length of the fold

And the area of this triangle = (1/2)x^2   = x^2/2

If the area of the square sheet of paper = 15cm^2, rhen one side = √15 cm

And the "white" area =  x (  √15 -x) + √15 ( √15 - x)  = (x + √15) (√15 - x)   =  

-x^2 + 15

So....since the two areas are equal, we have

x^2/2  = -x^2 + 15     add x^2 to both sides

3x^2 / 2   = 15      multiply both sides by 2/3

x^2 = 10        take the positive root of both sides

x = √10 in  = the length of the fold