What is ordered pairs and Equality of ordered pairs

If function f(x)={(k_1(x-pi)^2-1,xlepi),(k_2cosx,xgtpi):} is twice differentiable in ordered pair (k_1,k_2) . Find this ordered pair.

A man ordered 4 pairs of black socks and some pairs of brown socks. The price of a black pair is double that of a brown pair. While preparing the bill, the clerk did a mistake and interchanged the number of black and brown pairs. This increased the bill by 50%. The ratio of the number of black and brown pairs of socks in the original order was

Express in a+ib form and then represent as ordered pairs -1/2

Express in a+ib form and then represent as ordered pairs 3+sqrt(-7)

Express in a+ib form and then represent as ordered pairs 5-isqrt(-2)

Consider the system in ordered pairs (x,y) of real numbers sin x+sin y=sin(x+y) , |x|+|y|=1 . The number of ordered pairs (x,y) satisfying the system is