Answer:
-9x+12
Step-by-step explanation:
(-8x + 5) - (x – 7)
Distribute the minus sign
(-8x + 5) - x + 7
Combine like terms
(-8x -x+ 5+7)
-9x +12
Answer:
4.428 hours
Step-by-step explanation:
If the learning rate is 0.81, the slope of the learning curve is:

The time it takes to produce the n-th unit is:

If T1 = 8 hours, the time required to produce the seventh unit will be:

It will take roughly 4.428 hours.
To convert a percentage to decimal form, you need to divide the number in the percent by 100. In reality, that just looks like moving the decimal point to the left two places.
83% / 100 = 0.83
83% in decimal form is 0.83.
Hope that helped! =)
I'm assuming this is a system of equations you want solved so,
x = -y + 3
-2(-y+3)+4y = 6
2y - 6 + 4y = 6
6y = 12
y = 2
x + 2 = 3
x = -1
(-1,2)