Answer: 4
Step-by-step explanation:
Step-by-step explanation:
y=6+4x, as equation (iii)
=> -5x-(6+4x)=21
=> -5x-6-4x=21
=> -5x-4x-6=21
=> -9x-6=21
=> -9x=21+6
=> -9x=27
x= -3, by dividing both sides by -9
So, by inserting x in the first equation,
=> -4(-3)+y=6
=> 12+y=6
=> y=6-12
=> y= -6.
Therefore, x= -3 and y= -6
The amount of balls in a given layer can be found by squaring the layer it is in
4 layers
top layer (1st) is 1
2nd is 4
3rd layer is 9
4th is 16
add them up
1+4+9+16=30
30 in that pyramid
Answer:
11
Step-by-step explanation:
The two equations appear to be ...
- 12x +4y = 152
- 32x +12y = 420
These can be solved for y using Cramer's rule:
y = (152(32) -420(12))/(4(32) -12(12)) = -176/-16 = 11
The cost of the vegetarian lunch is 11.
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<em>Comment on Cramer's Rule</em>
For equations ...
ax +by =c
dx +ey = f
The solutions are ...
x = (bf -ey)/(bd -ea)
y = (cd -fa)/(bd -ea) . . . . note the denominators are the same expression
Once you memorize the pattern of products, this can be the simplest way to solve a pair of equations--especially if you only need one of the variable values.
