Please help me solve these practice problems. Thanks

39. y6 + 5y4 -3y2 -15 For problems 40 - 46, solve for the unknown in each equation. 40. y2 - 3y + 2= 0 44. x2 += x - WIN = = 0 41. x2 + 5x - 24 =0 45. t2 = 9t 42. t2 = 2t + 15 46. 3(t2 + 4) = 20t 43. z2 + 3z = -2 For problems 47 - 49, find the domain of the rational expression and express the answer in interval notation. 47. X 5x+30 48. 49. x+2 x +3 3x2+11x-42 14 50. Simplify: 5x-25 x2 - 25 51. Simplify: x2-5x-14 x2+x-2 For problems 52 - 57, perform the indicated operations. 52. 2 55. x-2x-15 x- -3x-18 4x 1-x x2 +7x+10 x2-x-30 7t+7 4t+4 53. 56. x3+x2-20 2x2-32 -6 15 x+4 4x2+20x 54. X ' - 49 x2 +8x+15 57. x4-5x-24 x2-10x+16 x2+4x-21 x2-2x-35 x2-25 x2-2x-15