No, when you plug is -5 for x and -1 for why, it ends up being -9 not -11. (-5,-1) is not a solution.
Answer:
x1 = 6 + 2√6 or x2 = 6 - 2√6
Step-by-step explanation:
x² - 12x + 12 = 0
We need to use formula:
a² - 2ab + b² = (a - b)².
x² - 12x = - 12
x² - 2*6x + 6²- 6² = - 12
(x - 6)² - 36 = -12
(x - 6)² = - 12 + 36
(x -6)² = 24
(x - 6) = √24 or (x-6) = -√24
(x - 6) = 2√6 or (x-6) = - 2√6
x = 6 + 2√6 or x = 6 - 2√6
Answer:
5
Step-by-step explanation:
I divided 
= 5
Х - 15 = 32
х = 32 + 15
x = 47 (answer)
-----------------------
47 - 15 = 32
32 = 32
х - 7.2 = 23,1
х = 23,1 + 7.2
х = 30,3 (answer)
---------------------------
30,3 - 7,2 = 23,1
23,1 = 23,1
Just measure the width (or height, if you'll be stacking the pennies
a mile high) of a penny, then divide 5280 feet by whatever you find.
This is a great activity for a class, and in fact a good way to start
the project. First take one penny, and work out an answer. Then get
100 pennies, and measure them; do the same calculation to see how many
pennies it will take to make a mile. There will probably be a
difference, because you can measure 100 pennies more accurately than a
single penny. Or maybe you have a micrometer that will measure one
penny precisely. Which is better can be a good discussion starter. And
don't forget to try it in metric, too.
Just to illustrate, using a very rough estimate of a penny's width,
let's say a penny is about 3/4 inch wide. The number of pennies in a
mile will be
5280 ft 12 in 1 penny
1 mile * ------- * ----- * ------- = 5280 * 12 * 4/3 pennies
1 mi 1 ft 3/4 in
This gives about 84,480 pennies. (This method of doing calculations
with units is very helpful, and would be worth teaching.)
If we measure 100 pennies as 6 ft 1 in, we will get
5280 ft 100 pennies
1 mile * ------- * ----------- = 5280 * 100 * 12 / 73 pennies
1 mi 6 1/12 ft
This gives us 86794.5205 pennies in a mile.
