Solve the given two equations and select the correct answer from the given options.
$I.$ $7x - 3y = 13$
$II.$ $5x + 4y = 40$

Construct a quadratic equation whose roots have the sum $= 6$ and product $= -16$.

Solve the given two equations and choose the correct answer from the given options.
$I.$ $x^{2}+12x+36=0$
$II.$ $y^{2}+15y+56=0$

$Quantity \, 1:$ Profit percent for a shopkeeper. The shopkeeper uses a faulty scale while buying cloth from a wholesaler. His scale measures $10 \%$ extra than the actual measurement. While selling,the shopkeeper gives $10 \%$ less and offers a discount of $10 \%$ to the customer.
$Quantity \, 2:$ Profit percent for a man who calculates his profit on the selling price. He marks up the cost of his item by $25 \%$ and then sells the item at a discount of $10 \%$.

The equation $e^x - x - 1 = 0$ has

Solve the given two equations and select the correct answer from the given options.
$I.$ $7x^{2} + 16x - 15 = 0$
$II.$ $y^{2} - 6y - 7 = 0$