a, <=> 35x - 25 = 24x + 8 <=> 11x = 33 <=> x = 3
b, <=> 5x + 10 - 3x + 9 = 15 <=> 2x = -4 <=> x = -2
<=> 99x + 18 - 16x + 4 = 39x + 6 - 72
<=> 44x = -88 <=> x = -2
d, \(\Leftrightarrow\dfrac{59-x}{19}-1+\dfrac{58-x}{18}-11=\dfrac{57-x}{17}-1+\dfrac{56-x}{16}-1\)
\(\Leftrightarrow\dfrac{40-x}{19}+\dfrac{40-x}{18}-\dfrac{40-x}{17}-\dfrac{40-x}{16}=0\)
\(\Leftrightarrow\left(40-x\right)\left(\dfrac{1}{19}+\dfrac{1}{18}-\dfrac{1}{17}-\dfrac{1}{16}\ne0\right)=0\Leftrightarrow x=40\)
Bài 3:
a: =>35x-25=24x+8
=>11x=33
hay x=3
b: =>5(x+2)-3(x-3)=15
=>5x+10-3x+9-15=0
=>2x-14=0
hay x=7
c: =>9(11x+2)-4(4x-1)=3(13x+2)-72
=>99x+18-16x+4-39x-6+72=0
=>44x=-88
hay x=-2
d: \(\Leftrightarrow\dfrac{59-x}{19}-1+\dfrac{58-x}{18}-1=\dfrac{57-x}{17}-1+\dfrac{56-x}{16}-1\)
=>40-x=0
hay x=40
