Question

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tìm x

 ( x -4 ) x3 + 7 = 240

3 x ( x - 5 ) + 8 x x = 62

Answer 1

[GV Nguyễn Trần Thành Đạt]

 ( x -4 ) x3 + 7 = 240

(x-4) x 3= 240 -7

(x-4) x 3 = 233

x-4= 233/3

x= 233/3 +4

x= 245/3

3 x ( X - 5 ) + 8 x X = 62

3 x X + 8 x X - 15 = 62

11 x X = 62 + 15

11 x X = 77

X=77:11

X=7

Answer 2

[HT.Phong (9A5)]

\(\left(x-4\right)\times3+7=240\)

\(\left(x-4\right)\times3=233\)

\(x-4=\dfrac{233}{3}\)

\(x=\dfrac{233}{3}+4\)

\(x=\dfrac{245}{3}\)

\(3\times\left(x-5\right)+8\times x=62\)

\(3\times x-15+8\times x=62\)

\(3\times x+8\times x=77\)

\(11\times x=77\)

\(x=\dfrac{77}{11}=7\)