Chapter 5: Exercises with Solutions

Section 5.2Vertex Form39. First complete the square to transform the function into vertex form a(x−h) 2 +k:f(x) = −5x 2 − 7x − 8(= −5 x 2 + 7 5 x + 8 )5(= −5 x 2 + 7 5 x + 49((= −5 x 2 + 7 5 x + 49100( (= −5 x + 7 10(= −5 x + 7 ) 2− 11110 20100 − 49100 + 8 )5)− 49) 2+ 111100Thus, h = − 7 10 , so the axis of symmetry is x = − 7 10 .)100 + 8 541. First complete the square to transform the function into vertex form a(x−h) 2 +k:f(x) = −2x 2 − 5x − 8= −2(x 2 + 5 )2 x + 4(= −2 x 2 + 5 2 x + 25((= −2 x 2 + 5 2 x + 2516( (= −2 x + 5 4(= −2 x + 5 ) 2− 39 4 816 − 25 )16 + 4)− 25 )16 + 4) 2+ 3916Thus, h = − 5 4 , so the axis of symmetry is x = − 5 4 .))Version: Fall 2007