13: multiply the amount by the tax rate (to make a percent a decimal move the decimal point 2 places to the left) and add the original amount and the taxed amount together. For 12 do above but then multiply the total by the tip rate and add together (basically the same as the tax again) :) I hope this helps
Answer:
The solutions are 
Step-by-step explanation:
we have

Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares

square root both sides


Answer:
x = 1.3
Step-by-step explanation:
15 - 4x = 2(3x + 1)
15 - 4x = 6x + 2
-2 -2
--------------------------
13 - 4x = 6x
+4x +4x
--------------------------
13 = 10x
/10 /10
---------------------------
1.3 = x
Answer:
7%
Step-by-step explanation:
Since percentages are out of 100. (Cent=100) Therefore 7/100 is 7%.
Answer:
2.7
Step-by-step explanation:
3% × 90 =
(3 ÷ 100) × 90 =
(3 × 90) ÷ 100 =
270 ÷ 100 = 2.7