Answer:
42−{(7+14)÷7}×4
42 - { 21/7} x 4
42 - 3 x 4
42 - 12
30
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<u>650 cannonballs
</u>
Explanation step by step:
upper layer = 1 ^ 2
second layer = 2 ^ 2
third layer = 3 ^ 2
layer 12 is 12 ^ 2
<u>The formula is:
</u>
<u>n * (n + 1) * (2n + 1) / 6
</u>
<u>n = 12
</u>
<u>12 (12 + 1) (2 * 12 + 1) / 6
</u>
<u>12 * 13 * 25/6 =
</u>
<u>650
</u>
<u>
</u>
There are 650 cannonballs in this pyramid.
Answer:

Step-by-step explanation:
[1] 2x + y = -1
[2] x - 2y = -8 <------- given linear equations
Graphic Representation of the Equations : ----> given in attatchment
y + 2x = -1 -2y + x = -8 < ----- point where they connect is shown in graph
Solve by Substitution :
// Solve equation [2] for the variable x
[2] x = 2y - 8
// Plug this in for variable x in equation [1]
[1] 2•(2y-8) + y = -1
[1] 5y = 15
// Solve equation [1] for the variable y
[1] 5y = 15
[1] y = 3
// By now we know this much :
x = 2y-8
y = 3
// Use the y value to solve for x
x = 2(3)-8 = -2
Solution :
{x,y} = {-2,3}
C^2-a^2=b^2 b^2=81-36=45 x^2/36-y^2/45=1?
Answer:
$1.60
Step-by-step explanation:
Amount of tax paid = percentage of tax to be paid x bill before tax
0.08 x $20 = $1.60