a, => -12x+60+21-7x=5
=> 71-19x=5
=> 19x = 71-5 = 66
=> x = 66 : 19 = 4
b, => 30x+60-6x+30-24=100
=> 24x+76 = 100
=> 24x = 100-76 = 24
=> x = 24 : 24 = 1
Tk mk nha
a, -12x-(-60)+21-7x=5
-19x+81=5
-19x=5-81
-19x=-76
x=-4
b, 30(x+2)-6(x-5)-24=100
30x+60-6x+30-24=100
36x+76=100
36x=34
x=34/36
a,-12(x-5)+7(3-x)=5
-12x+60+21-7x=5
81-19x =5
19x=76
=>x=4
b,30(x+2)-6(x-5)-24=100
30x+60-6x+30-24=100
24x+66=100
24x=34=>x=34/24=17/12
a, => -12x+60+21-7x=5
=> 71-19x=5
=> 19x = 71-5 = 66
=> x = 66 : 19 = 4
b, => 30x+60-6x+30-24=100
=> 24x+76 = 100
=> 24x = 100-76 = 24
=> x = 24 : 24 = 1
Tk mk nha $_$
\(a,-12\left(x-5\right)+7\left(3-x\right)=5\)
\(\Leftrightarrow-12x+60+21-7x=5\)
\(\Leftrightarrow19x=71-5=66\)
\(\Leftrightarrow x=66:19=4\)
\(a,-12\left(x-5\right)+7\left(3-x\right)=5\)
\(=>-12x+60+21-7x=5\)
\(=>-19x=5-81=-76\)
\(=>x=\frac{-76}{-19}=4\)
\(b,30.\left(x+2\right)-6.\left(x-5\right)-24=100\)
\(=>30x+60-6x+30-24=100\)
\(=>24x=100+24-30-60=124-90=34\)
\(=>x=\frac{34}{24}=\frac{17}{12}\)