a) 4×(-5)^2+2×(-15) b) 75-5x=1-(-9) c) 3 |x+14|=38 giúp với

0 bình luận về “a) 4×(-5)^2+2×(-15) b) 75-5x=1-(-9) c) 3 |x+14|=38 giúp với”

1. Đáp án:

   `a,4.(-5)^2+2.(-15)`

   `=4.25+2.(-15)`

   `=100+(-30)=70`

   `b,75-5x=1-(-9)`

   `\to75-5x=10`

   `\to5x=75-10`

   `\to5x=65`

   `tox=13`

   Vậy `x=13`

   `c,3|x+14|=38`

   `\to|x+14|=38/3`

   `\to` \(\left[ \begin{array}{l}x+14=\dfrac{38}{3}\\x+14=-\dfrac{38}{3}\end{array} \right.\) `\to` \(\left[ \begin{array}{l}x=-\dfrac{4}{3}\\x=-\dfrac{80}{3}\end{array} \right.\) 

   Vậy `x\in{-80/3;-4/3}`

   Trả lời

2. $a)4×$ $(-5)^{2}$ $+2×(-15)$

   $=4×10+2×(-15)$

   $= 40+(-30)$

   $=10$

   $b)$ 75 $-$ 5x $=$ $1-$ $(-9)$ 

   $75-5x = 10$ 

   $5x=75-10$

   $5x=65$

   $x=65:5$

   $x=13$

   $c)3 |x+14|=38$

   $|x+14|=38:3$

   $|x+14|=$ $\frac{38}{3}$

   $⇒$ $x + 14∈$ {$\frac{38}{3}$ ; $\frac{-38}{3}$}

   $+)$ $x+14=$ $\frac{38}{3}$ 

   $x=$ $\frac{38}{3}$ $-14$

   $x=$ $-$$\frac{4}{3}$ 

   $+)$ $x+14=$ $\frac{-38}{3}$

   $x=$ $\frac{-38}{3}$ $-14$

   $x=$ $-$ $\frac{80}{3}$ 

       Vậy $x∈${ $-$$\frac{4}{3}$ ; $-$ $\frac{80}{3}$ }

                      $@YuuSaji$

    

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