\(a,\left(x+3\right)\left(5-x\right)=0\\ \Rightarrow\left\{{}\begin{matrix}x+3=0\\5-x=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)

\(c,x+17⋮x+3\\ x+3+14⋮x+3\\ 14⋮x+3\\ x+3\inƯ\left(14\right)=\left\{\pm14;\pm7\pm2;\pm1\right\}\)

Từ đó bạn tìm những giá trị của x nha!

b: \(\Leftrightarrow8x=41\)

hay x=41/8

a. Đ

b. S

c. Đ

d. S

\(\text{(−1)+(−3)+...+(−199)+(−201)(−1)+(−3)+...+(−199)+(−201)}\)

=\(\text{−(1+3+...+199+201)=−(1+3+...+199+201)}\)

=\(\dfrac{\left(201+1\right).\left[\left(201-1\right)\right]:2+1}{2}\)

= \(\dfrac{-200.102}{2}=\dfrac{-20400}{2}=-10200\)

\(\text{17 + ( − 20 ) + 23 + ( − 26 ) + . . . + 53 + ( − 56 ) = [ 17 + ( − 20 ) ] + [ 23 + ( − 26 ) ] + . . . + [ 53 + ( − 56 ) ] = ( − 3 ) + ( − 3 ) + . . . + ( − 3 ) = ( − 3 ) . ( 7 ) = − 21}\)

\(\text{=17 + ( − 20 ) + 23 + ( − 26 ) + . . . + 53 + ( − 56 ) = [ 17 + ( − 20 ) ] + [ 23 + ( − 26 ) ] + . . . + [ 53 + ( − 56 ) ] = ( − 3 ) + ( − 3 ) + . . . + ( − 3 ) = ( − 3 ) . ( 7 ) = − 21}\)

 \(\text{ = ( − 3 ) + ( − 3 ) + . . . + ( − 3 )}\)

\(\text{= ( − 3 ) . ( 7 ) = − 21}\)

( 1/2 + 1/3 ) x 2/5

c1 = 5/6 x 2/5 = 1/3

c2 = 1/2 x 2/5 + 1/3 x 2/5

= 1/5 + 2/15 

= 1/3

3/5 x 17/21 x 2/5

c1 := 17/35 x 2/5 = 34/175

c2 : = (3/5 x 2/5) x 17/21 

= 6/25 x 17/21 

= 34/175?

( 1/3 - 1/5 ) x 1/2

c1 : = 2/15 x 1/2 

= 1/15

c2 : = 1/3 x 1/2 - 1/5 x 1/2

= 1/6 - 1/10

= 1/15