a,5x-20=0
<=>5x=20
<=>x=4
Vậy ....
b,<=>(x+5)(x-\(\dfrac{1}{2}\))=0
<=> x=-5 hoặc x=\(\dfrac{1}{2}\)
Vậy ....
d,<=>\(\dfrac{x-90}{10}+\dfrac{x-76}{12}+\dfrac{x-58}{14}+\dfrac{x-36}{16}-10=0\)
<=>\(\dfrac{x-90-10}{10}+\dfrac{x-76-24}{12}+\dfrac{x-58-42}{14}+\dfrac{x-36-64}{16}=0\)
<=>(x-100)(\(\dfrac{1}{10}+\dfrac{1}{16}+\dfrac{1}{14}+\dfrac{1}{12}\))=0
<=>x=100
Vậy....
a: =>5x=20
=>x=4
b: =>(x-1/2)(x+5)=0
=>x=1/2 hoặc x=-5
c: \(\Leftrightarrow\dfrac{2\left(x+5\right)}{6\left(x-2\right)}-\dfrac{3\left(x-2\right)}{6\left(x-2\right)}=\dfrac{3\left(2x-3\right)}{6\left(x-2\right)}\)
=>6x-9=2x+10-3x+6=-x+16
=>7x=25
=>x=25/7
d: \(\Leftrightarrow\left(\dfrac{x-90}{10}-1\right)+\left(\dfrac{x-76}{12}-2\right)+\left(\dfrac{x-58}{14}-3\right)+\left(\dfrac{x-36}{16}-4\right)=0\)
=>x-100=0
=>x=100