Question

3x+25=-2y ; 2x+y+10+0

Answer 1

Given Equations:-

• 3x + 25 = -2y
• 2x + y + 10 = 0

To find:-

• The value of x and y

Method:-

• Substitution method.

Solution:-

From given:-

3x + 25 = -2y

=> 3x + 2y = -25

2x + y + 10 = 0

=> 2x + y = -10

$\sf{3x + 2y = -25\longrightarrow[i]}$

$\sf{2x + y = -10\longrightarrow[ii]}$

From equation [i]

$\sf{3x + 2y = -25}$

= $\sf{3x = -25 - 2y}$

=> $\sf{x = \dfrac{-25-y}{3}}$

Substituting the value of x in equation (ii)

$\sf{2x + y = -10}$

= $\sf{2\bigg(\dfrac{-25-2y}{3}\bigg) + y = -10}$

= $\sf{\dfrac{-50-4y}{3} + y = -10}$

= $\sf{\dfrac{-50-4y+3y}{3} = -10}$

= $\sf{-50 -y = -10\times 3}$

= $\sf{-50-y = -30}$

=> $\sf{-y = -30+50}$

=> $\sf{-y = 20}$

=> $\sf{y = -20}$

Putting the value of y in equation (i)

$\sf{3x + 2y = -25}$

= $\sf{3x + 2\times (-20)= -25}$

=> $\sf{3x - 40 = -25}$

=> $\sf{3x = 40-25}$

=> $\sf{3x = 15}$

=> $\sf{x = \dfrac{15}{3}}$

=> $\sf{x = 5}$

Therefore,

• x = 5
• y = -20

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Answer 2

Answer:

$\Large\underline{\underline{\sf{ \color{magenta}{\qquad Given \qquad} }}}$

Given equations are,

3x+2y+25=0.............

3x+2y+25=0.............2x+y+10=0.................

From (ii), we can get

y=−2x−10

Substitute y value in equation (i) , we get

3x+2(−2x−10)+25=0

⇒3x−4x−20+25=0

⇒−x+5=0

∴x=5

Hence,

y=−2x−10=−2(5)−10=−10−10=−20

Solution is (x,y)=(5,−20)