x8 + 98x4 + 1

= (x8 + 2x4 + 1 ) + 96x4
= (x4 + 1)2 + 16x2(x4 + 1) + 64x4 - 16x2(x4 + 1) + 32x4
= (x4 + 1 + 8x2)2 – 16x2(x4 + 1 – 2x2) = (x4 + 8x2 + 1)2 - 16x2(x2 – 1)2
= (x4 + 8x2 + 1)2 - (4x3 – 4x)2
= (x4 + 4x3 + 8x2 – 4x + 1)(x4 - 4x3 + 8x2 + 4x + 1)

15x²-2x-1

=15x²-5x+3x-1

=(15x²-5x)+(3x-1)

=5x(3x-1)+(3x-1)

=(5x+1)(3x-1)

-79.81+79.31-79.50

=79.(-81+31+-50)

=79.(-100)

=-7900

K mk nhé bạn

change these following sentences into passtive voice.

1. The students have discussed the pollution problems since last week.

-> The pollution problems have been discussed by the students since last week.

2. Some people will interview the new president on TV.

-> The new president will be interviewed on TV .

3. How many languages do they speak in Canada?

-> How many languages are spoken in Canada by them?

4. Are you going to repair those shoes?

-> Are those shoes going to be repaired by you?

III. Write one word in each gap

70. Maybe you should write a letter …of……………………….. complaint to the manager.

71. When was the last time you had a ……day…………………….. off?

72. Hardly had the police officer come ………on………….. duty when he had to respond to an emergency.

73. My dad’s …………at……………….. work at the moment, I’m afraid. Can you call back later?

74. I am available to …………make……………….. an interview at your convenience.

75. He’s been …………doing……………….. this job for over thirty years.

76. Our company ………does………………….. a lot of business with Altech Industries.

77. Sol’s made an arrangement …with……………….. the wholesalers to deliver more frequently in future.

June’s got several years’ experience ………in………….. dealing with young children