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Mathematics

For solving each pair of equations, use the method of elimination by equating coefficients :

5y2x3=8\dfrac{5y}{2} - \dfrac{x}{3} = 8

y2+5x3=12\dfrac{y}{2} + \dfrac{5x}{3} = 12

Linear Equations

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Answer

Given equations :

5y2x3=8……….(1)y2+5x3=12……(2)\Rightarrow \dfrac{5y}{2} - \dfrac{x}{3} = 8 ……….(1) \\[1em] \Rightarrow \dfrac{y}{2} + \dfrac{5x}{3} = 12 ……(2)

Multiplying equation (1) by 30, we get :

30(5y2x3)=30×875y10x=240……(3)\Rightarrow 30\Big(\dfrac{5y}{2} - \dfrac{x}{3}\Big) = 30 \times 8 \\[1em] \Rightarrow 75y - 10x = 240 ……(3)

Multiplying equation (2) by 6, we get :

6(y2+5x3)=12×63y+10x=72………..(4)\Rightarrow 6\Big(\dfrac{y}{2} + \dfrac{5x}{3}\Big) = 12 \times 6 \\[1em] \Rightarrow 3y + 10x = 72 ………..(4)

Adding equations (3) and (4), we get :

⇒ 75y - 10x + 3y + 10x = 240 + 72

⇒ 78y = 312

⇒ y = 31278\dfrac{312}{78} = 4.

Substituting value of y in equation (1), we get :

5×42x3=810x3=8x3=108x=3×2=6.\Rightarrow \dfrac{5 \times 4}{2} - \dfrac{x}{3} = 8 \\[1em] \Rightarrow 10 - \dfrac{x}{3} = 8 \\[1em] \Rightarrow \dfrac{x}{3} = 10 - 8 \\[1em] \Rightarrow x = 3 \times 2 = 6.

Hence, x = 6 and y = 4.

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