\(\text{30.(x+2)-6.(x+5)-24x=100}\)
\(30x+60-6x-30-24x=100\)
\(30x-6x-24x=100+30-60\)
\(0=70\\ \Rightarrow x\in\varnothing\)
\(\text{-12.(x-15)+7.(3-x)=15}\)
\(-12x+180+21-7x=15\)
\(-12x-7x=15-21-180\)
\(-19x=-186\)
\(x=\frac{186}{19}\)
\(\text{-(574+x)=(x-12-741)-23}\)
\(-574-x=x-12-741-23\)
\(-x-x=-752+574\)
\(-2x=-178\)
\(x=89\)
chúc bạn học tốt !!!
cảm ơn Nguyễn ngọc linh nhiều nha