61 Elsa tänker på ett tal. Hon multiplicerar talet med 8 och subtraherar sedan med 70 . Hon får då 250 . Vilket tal tänker Elsa på? B PK

Diketahui sistem persamaan tinier berikut ini : \[ \begin{array}{l}-1 x+y+2 z=2 \\ 3 x-1 y+z=6 \\ -1 x+3 y+4 z=4\end{array} \] Tentukan solusi persamaan linear tersebut menggunakan metode gauss!

1) \( \frac{10 x+8}{3 a-b}-\frac{9 x+5}{3 a-b}= \)

8. \( \frac{\sqrt{27 a^{3} b^{6}}}{\sqrt{3 a b^{6}}-5 a b^{2}}= \)

Roger was told to think of a number, add 20 , then divide the result by 3 . The answer was Jower than Roger's original number. Deteruine the range of possible numbers Roger may have originally chosen.

In the \( x y \)-plane, a parabola has vertex \( (9,-14) \) and intersects the \( x \)-axis at two points. If the equation of the parabola is written in the form \( y=a x^{2}+b x+c \) where \( a, b \), and \( c \) are constants, which of the following could be the value of \( a+b+c \) ? (A) -23 (B) -19 (D) -12