Using elimination, we add the equations, but this time from left to right. This process wants to elimination a variable. So 2x plus -2x equals 0. Moving on the next variable, 6y plus -y is 5y. On to the last variable, 18 plus 12 is 30. So we have this equation, 5y=30. 30/5 is 6, so y=6. We plug 6 into y in one of the equations you choose. In this case, I'm going to use the first equation. Plugging 6, we have this equation, 2x plus 36 is 18. 18-36 is -18. We then have this equation, 2x=-18. We know -9 times 2 is -18, so our x value is -9, So, our y=6, and our x=-9.
Answer:
no it is not
Step-by-step explanation:
Answer:
(-5,5)
Step-by-step explanation:
Multiply the first equation by -2,and multiply the second equation by 1.
−2(x+5y=20)
1(2x−7y=−45)
Becomes:
−2x−10y=−40
2x−7y=−45
Add these equations to eliminate x:
−17y=−85
Then solve−17y=−85for y:
(Divide both sides by -17)
y=5
x+5y=20
Substitute 5 for y in x+5y=20:
x+(5)(5)=20
x+25=20(Simplify both sides of the equation)
x+25+−25=20+−25(Add -25 to both sides)
x=-5
We know that the profit from an item is the sale price minus the cost price. Thus,
1269 - 0.2x² - 830 - 398x
P(x) = -0.2x² - 398x + 439
Local maxima are located at the points where the first derivative of a function are 0
P'(x) = -0.4x - 398
398 = -0.4x
x = -995
There is only one maximum so the average value is -995
