Answer:
$47.92
Step-by-step explanation:
20% discount: $599 * 80% = $479.2 before tax
15% tax added: $479.2 + $71.88 = $551.08
Saved money: $599-$551.08= $47.92
Formula For Factoring Trinomials (when a =1)
It's always easaier to understand a new concept by looking at a
specific example so you might want to do that first. This formula works
when 'a' is 1. [ In other words, we will use this approach whenever the
coefficient in from of x2 is 1.
1) identify a,b, and c in the trinomial ax2 + bx+c
2) write down all factor pairs of c
3) identify which factor pair from the previous step sums up to b
4) Substitute factor pairs into two binomials
This is the commutative property, because the order in which you multiply does not change the product.
Simplifying
b2 + -4b + -14 = 0
Reorder the terms:
-14 + -4b + b2 = 0
Solving
-14 + -4b + b2 = 0
Solving for variable 'b'.
Begin completing the square.
Move the constant term to the right:
Add '14' to each side of the equation.
-14 + -4b + 14 + b2 = 0 + 14
Reorder the terms:
-14 + 14 + -4b + b2 = 0 + 14
Combine like terms: -14 + 14 = 0
0 + -4b + b2 = 0 + 14
-4b + b2 = 0 + 14
Combine like terms: 0 + 14 = 14
-4b + b2 = 14
The b term is -4b. Take half its coefficient (-2).
Square it (4) and add it to both sides.
Add '4' to each side of the equation.
-4b + 4 + b2 = 14 + 4
Reorder the terms:
4 + -4b + b2 = 14 + 4
Combine like terms: 14 + 4 = 18
4 + -4b + b2 = 18
Factor a perfect square on the left side:
(b + -2)(b + -2) = 18
Calculate the square root of the right side: 4.242640687
Break this problem into two subproblems by setting
(b + -2) equal to 4.242640687 and -4.242640687. b + -2 = 4.242640687
Simplifying
b + -2 = 4.242640687
Reorder the terms:
-2 + b = 4.242640687
Solving
-2 + b = 4.242640687
Solving for variable 'b'.
Move all terms containing b to the left, all other terms to the right.
Add '2' to each side of the equation.
-2 + 2 + b = 4.242640687 + 2
Combine like terms: -2 + 2 = 0
0 + b = 4.242640687 + 2
b = 4.242640687 + 2
Combine like terms: 4.242640687 + 2 = 6.242640687
b = 6.242640687
Simplifying
B = 6.242640687
Subproblem 2
b + -2 = -4.242640687
Simplifying
b + -2 = -4.242640687
Reorder the terms:
-2 + b = -4.242640687
Solving
-2 + b = -4.242640687
Solving for variable 'b'.
Move all terms containing b to the left, all other terms to the right.
Add '2' to each side of the equation.
-2 + 2 + b = -4.242640687 + 2
Combine like terms: -2 + 2 = 0
0 + b = -4.242640687 + 2
b = -4.242640687 + 2
Combine like terms: -4.242640687 + 2 = -2.242640687
b = -2.242640687
Simplifying
b = -2.242640687
