I am going to explain this using the substitution method, considering it appears to be the best in this situation.
We know (from the bottom equation) that y can equal 3x+20. Using this knowledge, we substitute the y in the top equation for 3x+20. Now, we have an equation that looks like this:
3x+20=x^2+2x
Now we need to move x to one side and then do some radicals (square roots).
Subtract the 2x on the right (since it is smaller, negatives = NONONO), which will give you
x+20=x^2
Now, we take the square root of both sides to get
rad(x+20)=x
Now we have to simplify. 20 doesn't have a square root, but 4 goes into 20, and 4 has a square root of 2. This now becomes
2rad(x+5)
This doesn't simplify any further... we have a problem... no way to isolate x as far as my knowledge goes... Sorry, can't help you any further than that, but another person or your teacher might be able to. R.I.P...
X=750+125.75x
subtract to variable (x) on one side
x-125.75x=750+125.75x-125.75x
-124.75x=750
divide -124.75 to get variable (x) by itself
-124.75x/-124.75=750/-124.75
x=-3000/499
or
x=-6 6/499
or
x=-6.01202
Answer:
could you please explain me the exact question
Alright here it is:
-2/7x + y = -7
The correct answer is letter D, Region D contains the solution for the system of inequalities.
