Question

Tìm x \(\varepsilon\)Z

a)    2.(4x-8)-7(3+x)=|-4|.(3-2)

b)    3.|x-3|=15-|-9|+7.|-3|-(-24)

c)     4(x-5)-7(5-x)+10(5-x)= -3

d)     6.|x-3|-9.|x-3|=-21

 

Answer 1

\(a)2\left(4x-8\right)-7\left(3+x\right)=|-4|\left(3-2\right)\)

\(\Leftrightarrow8x-16-21-7x=4\)

\(\Leftrightarrow\left(8x-7x\right)=16+21+4\)

\(\Leftrightarrow x=41\)

\(b)3|x-3|=15-|-9|+7|-3|-\left(-21\right)\)

\(\Leftrightarrow3|x-3|=15-9+7.3+21\)

\(\Leftrightarrow3|x-3|=15-9+21+21\)

\(\Leftrightarrow3|x-3|=48\)

\(\Leftrightarrow|x-3|=16\)

\(\Leftrightarrow\orbr{\begin{cases}x-3=-16\\x-3=16\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=-13\\x=19\end{cases}}\)

\(c)4\left(x-5\right)-7\left(5-x\right)+10\left(5-x\right)=-3\)

\(\Leftrightarrow4x-20-35+7x+50-10x=-3\)

\(\Leftrightarrow4x+7x-10x=20+35-50-3\)

\(\Leftrightarrow x=2\)

\(d)6|x-3|-9|x-3|=-21\)

\(\Leftrightarrow|x-3|\left(6-9\right)=-21\)

\(\Leftrightarrow-3|x-3|=-21\)

\(\Leftrightarrow|x-3|=7\)

\(\Leftrightarrow\orbr{\begin{cases}x-3=-7\\x-3=7\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=-4\\x=10\end{cases}}\)

Answer 2

thanks you bạn nhiều nhen