Chapter 4 Quadratic Functions and Factoring - 4.7 Complete the Square - 4.7 Exercises - Mixed Review - Page 291: 82

See the graph

We are given: $x \geq 0$ $x+y \lt 4 \rightarrow y \lt 4-x$ The blue region represents $x \geq 0$. The green region represents $x+y \lt 4$. The solution of the system is the intersection of the blue and green regions.