Answer: a
Step-by-step explanation:
Your answer is 3. 3*2= 6 6-7= -1 and if -1 is increased by 2 you get 1. So the mystery number is 3 I hope this helps:)
Answer:
East and west side= 5 foot
South and north side = 10 foot
Area = 50 foot^2
Step-by-step explanation:
We know that:
East and west fencing cost= $4 per foot
South and north fencing cost $2 per foot
So, we can consider:
x= south and north fencing
y= east and west fencing
Then we create an equation representing the case:
Total cost = (south+north)*$2 + (east+west)*$4
80 =(x+x)*2 + (y+y)*4
80 =(2x)*2 + (2y)*4
80 =4x + 8y
80 =4*(x+2y)
80/4 =x+2y
20 = x+2y
x= 20-2y
We can calculate the area as width * length:
Area = length * width
Area= x * y
Area= (20 - 2y) * y
area= 20y - 2y^2
Next step is to find the "y" value for the maximum area so you can derivate and equal to 0 to find maximums:
d(20y - 2y^2)/dy = 20 - 2*2y = 20 - 4y
20 - 4y = 0
20 = 4y
y = 20/4
y = 5
If y = 5, then:
x = 20 - 2y
x = 20 - 2*5
x = 20 - 10
x = 10
Answer: 4
Step-by-step explanation: so multiply 3 by 10. Then subtract 10 from both sides so you should be left with 20=5r and then you divide both sides by 5 to equal 4