Answer:
= 9
Step-by-step explanation:
Given that,
Asn expression :
We need to evaluate the above expression.
We know that, 
So,
or
So, the value of is 9. Hence, the correct option is (b).
Answer:
it's all about materialistic gain.
To solve this problem, let us first assign some
variables. Let us say that:
x = pigs
y = chickens
z = ducks
From the problem statement, we can formulate the
following equations:
1. y + z = 30 --->
only chicken and ducks have feathers
2. 4 x + 2 y + 2 z = 120 --->
pig has 4 feet, while chicken and duck has 2 each
3. 2 x + 2 y + 2 z = 90 --->
each animal has 2 eyes only
Rewriting equation 1 in terms of y:
y = 30 – z
Plugging this in equation 2:
4 x + 2 (30 – z) + 2 z = 120
4 x + 60 – 2z + 2z = 120
4 x = 120 – 60
4 x = 60
x = 15
From the given choices, only one choice has 15 pigs. Therefore
the answers are:
She has 15 pigs, 12 chickens, and 18 ducks.
Answer:
Step-by-step explanation:
-2x + 3y – 4z = 8 ----------------(I)
5x – 3y + 5z = -8 -----------------(II)
7x – 3y + 3z = 8 ------------------(III)
Add equation (I) & (II) and thus y will be eliminated
(I) -2x + 3y – 4z = 8
(II) <u>5x – 3y + 5z = -8</u> {Add}
3x + z = 0 ------------------------(A)
Multiply equation (II) by (-1) and then add with equation (III). Thus y will be eliminated.
(II) * (-1) -5x + 3y - 5z = +8
<u>7x – 3y + 3z = 8</u> {Add}
2x -2z = 16 ---------------(B)
Multiply equation (A) by 2 and then add. Thus z will be eliminated and we will get the value of x
(A) * 2 6x + 2z = 0
(B) <u>2x - 2z = 16</u> {Add}
8x = 16
Divide both sides by 8
x = 16/8
x = 2
Plugin x = 2 in equation (A)
3x + z = 0
3*2 + z = 0
6 + z = 0
z = -6
Plug in x = 2 and z = - 6 in equation (I)
-2x +3y - 4z = 8
-2*2 + 3y - 4*(-6) = 8
-4 + 3y + 24 = 8
3y + 20 = 8
3y = 8 - 20
3y = -12
y = -12/3
y = -4
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