1) Venn Diagram is used to organize data
2) Four circles. Three intersection circles, and one which contains other three circles
3) In the intersection area of three circles.
4) In the circle which contains other three circles, but not inside any of the intersecting circles.
FOIL is a mnemonic rule for multiplying binomial (that is, two-term) algebraic expressions.
FOIL abbreviates the sequence "First, Outside, Inside, Last"; it's a way of remembering that the product is the sum of the products of those four combinations of terms.
For instance, if we multiply the two expressions
(x + 1) (x + 2)
then the result is the sum of these four products:
x times x (the First terms of each expression)
x times 2 (the Outside pair of terms)
1 times x (the Inside pair of terms)
1 times 2 (the Last terms of each expression)
and so
(x + 1) (x + 2) = x^2 + 2x + 1x + 2 = x^2 + 3x + 2
[where the ^ is the usual way we indicate exponents here in Answers, because they're hard to represent in an online text environment].
Now, compare this to multiplying a pair of two-digit integers:
37 × 43
= (30 × 40) + (30 × 3) + (7 × 40) + (7 × 3)
= 1200 + 90 + 280 + 21
= 1591
The reason the two processes resemble each other is that multiplication is multiplication; the difference in the ways we represent the factors doesn't make it a fundamentally different operation.
There shouldn't be a negative in front of one of the equations.
Let the number be n. Then 2(n-10) = 6n + 14.
Multiplying out the left side, 2n - 20 = 6n + 14. Thus, -34=4n, and n = -17/2.
