## Algebra 1: Common Core (15th Edition)

The measures of the two angles are equal so we can put them into an equation. 4x+3=45 (we subtract 3 from both sides of the equation) 4x+3-3=45-3 (simplify) 4x=42 (Divide each side by 4 to isolate the variable) x=42$\div$4=10.5 Thus, x=10.5