Answer:
2. x = -16 y = -10.5
3. x = 4
4. x = 3 y = 2/9 or 0.2222222222222...
Step-by-step explanation:
2.
in my stategy, you plus -5x + 8y = -4 with 6x - 8y = -12
+8y and -8y could delete each other, then y will be gone.
-5x + 6y = 1x = x because -5 + 6 = 1
so then you could got x = (-4) + (-12) which means x = -16
if x = -16 that will then means
(-5) x (-16) + 8y = -4
80 + 8y = -4
8y = -4 - 80
8y = -84
y = -10.5
3.
This question has already given you that y = -5
that means, 3x + 6 × (-5) = -18
3x + -30 = -18
3x = -18 - (-30)
3x = 12
x = 4
4.
Like the 2. qestion, you first plus the 2 equation together,
+9y + -9y = 0
-7x + 4x = -3x
-19 + 10 = -9
than means
-3x = -9
x = 3
then put the x = 3 in one of the equation.
4 x 3 - 9y = 10
12 - 9y = 10
-9y = 10 - 12
-9y = -2
-7 x 3 + 9y = -19
-21 + 9y = -19
9y = -19 + 21
9y = 2
y = 2/9 or 0.2222222222...
Wish this could help you!
Answer:
B, 2,010
Hope this helps have a nice day/night :)
Answer:
He has 30 penguins and 10 cats.
Step-by-step explanation:
Let's define the variables:
C = number of cats.
P = number of penguins.
We know that he has a total of 40 pets, then:
C + P = 40
We also know that the total heads (40 heads, each animal has one) plus the number of wings (P*2, each penguin has 2) is equal to the number of feet of his pets (4*C + 2*P, because each cat has 4 paws, and each penguin has 2)
Then we have the equation:
40 + 2*P = 4*C + 2*P
Notice that in the second equation we have the term 2*P in both sides of the equation, then we can just subtract 2*P in both sides to get:
(40 + 2*P) - 2*P = 4*C + 2*P - 2*P
40 = 4*C
Now with this, we can find the value of C.
40/4 = C = 10
Then he has 10 cats.
Now we can replace this in the equation:
P + C = 40
to find the value of P
P + 10 = 40
P = 40 - 10 = 30
P = 30
He has 30 penguins.
3, would be 9.75
4, would be 13
5, would be 16.25
6, would be 19.50
7, would be 22.75
8, would be 26
9, would be 29.25
OR 3.25x = y (y being 3-9)
30 x 28= 840
It's would beat 840 times in half an hour.
