Just get only one of the placeholder on one side by itself
and do the same thing to both sides so it stays equal
3x+7=5x-21
add 21 to both sides
3x+28=5x
subtract 3x from obht sides
28=2x
sivide both sides by 2
14=x
3x-4y=10
-20-x+2y=10 then -30+2y=x now plug this in the other equation:
3(-30+2y)-4y=10
-90+6y-4y=10
2y=100
y=50
To find where the second derivative of the function changes sign, from negative to positive, or vice-versa. So, we find the second derivative of the given function.
you can find a_6:
