\( \begin{aligned} x+2 y+3 z & =10 \\ 2 x+5 y+6 z & =5 \\ x+z & =20\end{aligned} \quad \) จะได้ว่า \( x+y+z=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \)

Convert the following to Symbolic form: a. Multiply the input number by 8 then divide by 2 b. Subtract 7 from the input number then multiply by 8 c. Divide the input number by 4 then add 7 d. Multiply the input number into the equation of \( 5+5 \)

Convert the following to Verbal form: activity \( 100-9 x \) b. \( 7 a+43 \) c. \( x \) \( 4+5 \) d. \( y(12-9) \)

(b) \( m^{4} n \square \div m \square n^{5}=m^{2} n \)

\( y \) in un punto di ordinata non negativa. (199) È data la funzione \( y=(2 k+4) x+2 k+1, \operatorname{con} k \in R \). Stabilisci per quali valori di \( k \) la retta grafico della funzio- he forma con l'asse \( x \) un angolo ottuso.

1. ข้อใดไม่ใช่ตัวประกอบของพหุ นามดีกรีสอง \( x^{2}+3 x-18 \) ox-3 x \( x+2 \) x+6 \( (x-3)(x+6) \)