Picture won't work, here is a link--QUESTION 1
http://www.engr.colostate.edu/ECE204/SP15/homework/supplement17_1.pdf
Solution
For a diode to be forward biased, the voltage at positive terminal should be greater than negative
side.
The voltage applied on positive side is at max 5V connected via a resistor.
D1 has 5v on negative side. so it is reverse biased.
D2 has -5V on negative side, which is less than that on positive side so it is forward biased.
D3 has 5v on negative side. so it is reverse biased.
D4 has -5V on negative side, which is less than that on positive side so it is forward biased.
Given a 0.7V drop occurs for forward biased diodes. So
Vout - (-5V) = 0.7
Vout = -4.3V