( ) 78. = 0 x (2 )2 (2 ) ( ) (1 )2 (1 ) − − − The zeros of = 3 − + 5 − + + 20 H x x x x x = 0 2 are H 5 (2 = − → = − 2 and 2. The of the graph of are u x u x x-intercepts H 2 Let 3 )2 5 (u (u + − = + − = 5) 4) 0 20 0 u u 2 and 2. 3 + 5 = 0 u − = 81. 4 ( ) u or = 0 G x 0 = u = 4 u − = 0 x x −5 4 − = −5 − 2 2 x x Let = → = u x u x = 4 2 = 7 x = x − 4u = 0 u 2 −2 ( ) (2 )2 (2 ) zeros of = − + − − 20 are H x x x (u −2 and 7. The of the graph of are x-intercepts H − 4) = 0 u − 4 = −2 and 7. u = 0 or u = 0 u ( ) = P x 79. 4 = x 0 = 0 x 4 The 2 2 ( ( + − + − 2 1)2 5 1) x x = 0 = 0 = 4 = 16 x x 3 = 0 Let ( = + 1 → = + u x u2 x 1)2 2u − 5u − 3 = 2 (0) = 0 − 4 0 = 0 G 0 (2u (u (16) + − = 16 − 4 16 = 16 − 16 = 0 1) 3) G = 0 2u + 1 = 0 are 0 and 16. The − 3 = ( ) x u or = − The zeros of G x x 0 4 + 1 = 3 x 1 u = 3 u of the graph of are 0 and 16. x-intercepts G + = − 1 x 82. = 2 ( ) x = 0 f x 1 2 + 8 x 3 x
78. H ( x ) = 0 (2 − x )2 + (2 − x ) − 20 = 0 The zeros of H ( x ) = 3 (1 − x )2 + 5 (1 − x ) + 2 are 5 Let u = 2 − x → u 2 = (2 − x )2 and 2. The x-intercepts of the graph of H are 3 5 u 2 + u − 20 = 0 (u + 5) (u − 4) = 0 and 2. 3 u + 5 = 0 or u − 4 = 0 81. G ( x ) = 0 u = −5 u = 4 x − 4 x = 0 2 − x = −5 2 − x = 4 Let u = x → u 2 = x x = 7 x = −2 u 2 − 4u = 0 79. The zeros of H ( x ) = (2 − x )2 + (2 − x ) − 20 are −2 and 7. The x-intercepts of the graph of H are −2 and 7. P ( x ) = 0 u (u − 4) = 0 u = 0 or x = 0 u − 4 = 0 u = 4 x = 4 2 2 2 ( x + 1)2 − 5 ( x + 1) − 3 = 0 x = 0 = 0 x = 4 = 16 Let u = x + 1 → u2 = ( x + 1)2 2u 2 − 5u − 3 = 0 (2u + 1) (u − 3) = 0 G (0) = 0 − 4 0 = 0 G (16) = 16 − 4 16 = 16 − 16 = 0 2u + 1 = 0 or u − 3 = 0 The zeros of G ( x ) = x − 4 x are 0 and 16. The 1 u u = 3 x + 1 = 3 x-intercepts of the graph of G are 0 and 16. x + 1 = − 1 x = 2 82. f ( x ) = 0 2 x + 8 x 3
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