B. Use the correct form of the word given to complete each sentence

1. What type of clothing is...... for survival at these altitudes?(need)

He wore dark glasses to avoid being recognized

to

1. What type of clothing is...... for survival at these altitudes?(need)

1. All dancers and musicians wore....... costume.

a. comfortable

b. convenient

c.different

d. traditional

B=(5-2x)³-(3x+5)(5-3x)

=125-150x+60x²-8x³-(25-9x²)

=125-150x+60x²-8x³-25-9x²

=-8x³+51x²-150x+100

bài 1

A=2x³+3(x-1)(x+1)-5x(x+1)

=2x³+3(x²-1)-5x²-5x

=2x³+3x²-3-5x²-5x

=2x³-2x²-5x-3

(x+4)²-(1+x)(x-1)=16

\(\Rightarrow\)x²+8x+16-(x²-1)=16

\(\Rightarrow\)x²+8x+16-x²+1=16

\(\Rightarrow\)8x+17=16

\(\Rightarrow\)8x=16-17

\(\Rightarrow\)8x=-1

\(\Rightarrow\)x=\(\dfrac{-1}{8}\)