Does anyone know how to solve this (4-7i) - (-3+6i) ?

Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters.

Each month, a shopkeeper spends 5x + 14 dollars on rent and electricity. if he spends 3x−5 dollars on rent, how much does he spend on electricity? for which value(s) of x is the amount the shopkeeper spends on electricity less than $100? explain how you found the value(s).

What is the value of x in the equation 2(x-4) = 4(2x + 1)?