Đề bài thế này đúng ko: 3. 1/3y + 16. 3/4 = -13,25

3 . 1/3 y + 16.3/4=-13,25

y + 12 = -13,25

y = -13,25 -12

y= -25,25

Giải:

3 1/3y + 16 3/4 = -13,25

10/3y + 67/4 = -53/4

10/3y            = -53/4 - 67/4

10/3y            = -30

       y            = -30 : 10/3

       y            =-9

Chúc bạn học tốt!

Lời giải:

a. $y+30\text{%}y=-1,3$

$y+0,3y=-1,3$

$y(1+0,3)=-1,3$

$y.1,3=-1,3$

$y=(-1,3):1,3=-1$

b.

$y-25\text{%}y=\frac{1}{2}$

$y-0,25y=0,5$

$y(1-0,25)=0,5$

$y.0,75=0,5$

$y=0,5:0,75=\frac{2}{3}$

c.

\(3+\frac{1}{3}y+16+\frac{3}{4}=-13,25\)

$\frac{1}{3}y+19,75=-13,25$
$\frac{1}{3}y=-13,25-19,75=-33$
$y=-33:\frac{1}{3}=-99$

\(3\dfrac{1}{3}x+16\dfrac{3}{4}=-13,25\)

\(\Rightarrow\dfrac{10}{3}x+\dfrac{67}{4}=-\dfrac{53}{4}\)

\(\Rightarrow\dfrac{10}{3}x=-\dfrac{53}{4}-\dfrac{67}{4}\)

\(\Rightarrow\dfrac{10}{3}x=\dfrac{-120}{4}\)

\(\Rightarrow\dfrac{10}{3}x=-30\)

\(\Rightarrow x=-30:\dfrac{10}{3}\)

\(\Rightarrow x=-9\)

Vậy: ...

\(3\dfrac{1}{3}x+16\dfrac{3}{4}=-13,25\)

\(\Leftrightarrow\dfrac{10}{3}x+\dfrac{67}{4}=\dfrac{-53}{4}\)

\(\dfrac{10}{3}x=\dfrac{-53}{4}-\dfrac{67}{4}\)

\(\dfrac{10}{3}x=\dfrac{-120}{4}=-30\)

\(x=-30.\dfrac{3}{10}\)

\(x=\dfrac{-90}{10}=-9\)

\(\dfrac{31}{3}x+16\dfrac{3}{4}=-13,25\)

\(\dfrac{31}{3}x=\dfrac{-53}{4}-\dfrac{67}{4}\)

\(\dfrac{31}{3}x=-30\)

\(\Rightarrow x=-30:\dfrac{31}{3}\)

\(\Rightarrow x=\dfrac{-90}{31}\)

=>10/3x=3,5

=>x=21/20

4/16 và 3/4

\(1\frac{1}{3}\cdot x+16\frac{3}{4}=13,25\)

\(\frac{4}{3}\cdot x=13,25-16\frac{3}{4}\)

\(\frac{4}{3}\cdot x=-3,5\)

\(x=-3,5:\frac{4}{3}\)

\(x=-2,625\)

\(3\frac{1}{3}x+16\frac{3}{4}=-13,25\)

\(=>\frac{10}{3}x+\frac{67}{4}=\frac{-53}{4}\)

\(\frac{10}{3}x=-30\)

x = -30 : \(\frac{10}{3}\)

= > x = -9