Question

[Hà Phúc Luân]

4y + x3 = 91

Tính tổng x và y

Answer 1

[༺༒༻²ᵏ⁸]

\(4y+x3=91\)

\(4y+3x=91\)

\(3y+y+3x=91\)

\(3\left(x+y\right)+y=91\)

\(\left(x+y\right)+y=91\div3\)

\(\left(x+y\right)+y=\frac{91}{3}\)

\(x+y+y=\frac{91}{3}\)

\(x+2y=\frac{91}{3}\)

\(2x+2y=2\times\frac{91}{3}\)

\(2x+2y=\frac{91}{6}\)

\(2\left(x+y\right)=\frac{91}{6}\)

\(x+y=\frac{91}{6}\div2\)

\(x+y=\frac{91}{6}\times\frac{1}{2}\)

\(x+y=\frac{91}{12}\)