The general form of a quadratic equation is that which is expressed in a form,
ax² + bx + c = 0
To write the equation in its general form, eliminate the decimal by multiplying the equation by 10. It now becomes,
3x² + 50x - 70 = 0
The value of b is therefore 50 and the answer is the second choice.
For this problem, let x be the number of children and y for adults. Formulate the equations: 1st equation, x + y = 3,200 and 2nd equation 5x + 9y = 24,000. Re-arrange 1st equation into x = 3200 - y. Then, substitute into 2nd equation, 5(3,200-y) + 9y = 24,000. Then, solve for y. The 16,000 - 5y + 9y = 24000. Final answer is, y = 2000 adults went to watch the movie.
Since 4 is between 2 & 5 you input it into the middle equation.
x=4
so the answer is 4!
I suppose you mean

Differentiate one term at a time.
Rewrite the first term as

Then the product rule says

Then with the power and chain rules,

Simplify this a bit by factoring out
:

For the second term, recall that

Then by the chain rule,

So we have

and we can simplify this by factoring out
to end up with
