It is 10 to 1 significant figures
-x^2 -2x-6
Multiply everything by negative one to make X positive
X^2+2x+6
Use quadratic formula
-2+-sq rt of 2^2-4(1)(6) / 2
-2+-sqrt of -20 /2
-2+ 2i/2. -2-2i/2
-2+i. -2-i
Look at it this way:
-- Since the two groups have the ratio of 4 to 7, then the first group has 4 parts
and the other group has 7 parts.
-- If the first group has 4 parts and the other group has 7 parts, then they have
11 parts all together.
-- Those 11 parts are all parts of 33. There must be ( 33 / 11 ) = 3 items in each part.
Now you can go back to the groups . . .
-- The first group has 4 parts.
With 3 items in each part, that's (4 x 3) = 12 items.
-- The other group has 7 parts.
With 3 items in each part, that's (7 x 3) = 21 items.
When the linear dimensions are changed by a factor of 2, the area is changed by a factor of 2^2 = 4.
The total surface area is multiplied by 4.
