Question

1.2x+3y=0 -3x-4y=-7 solution​

Answer 1

Answer:

x = 15 and y = -10

Step-by-step explanation:

2x+3y=0 -------- eq (1)

3x+4y=5 -------- eq (2)

→ Multiply equation (1) by 3 and equation (2) by 2

Now the equations becomes →

6x + 9y = 0

6x + 8y = 10

__________ [Subtract both the equations]

(-) (-) (-)

__________

0 + y = -10

__________

→y = -10

Now substituting the value of y in equation (1)

→2x + 3y = 0

→2x + 3(-10) = 0

→2x - 30 = 0

→2x = 30

→x =  

→x = 15

Answer 2

Answer

$\sf \dashrightarrow 1.2x + 3y = 0 \: \: --- (i)$

$\sf \dashrightarrow -3x - 4y = -7 \: \: --- (ii)$

By first equation,

$\sf \dashrightarrow 1.2x + 3y = 0$

$\sf \dashrightarrow 1.2x = -3y$

$\sf \dashrightarrow x = \dfrac{-3y}{1.2}$

Now, let's find the value of y by second equation.

$\sf \dashrightarrow -3x - 4y = -7$

$\sf \dashrightarrow -3 \bigg( \dfrac{-3y}{1.2} \bigg) - 4y = -7$

$\sf \dashrightarrow \dfrac{9y}{1.2} - 4y = -7$

$\sf \dashrightarrow \dfrac{9y - 4.8y}{1.2} = -7$

$\sf \dashrightarrow \dfrac{4.2y}{1.2} = -7$

$\sf \dashrightarrow 4.2y = -7 \times 1.2$

$\sf \dashrightarrow 4.2y = -8.4$

$\sf \dashrightarrow y = \dfrac{-8.4}{4.2}$

$\sf \dashrightarrow y = -2$

Now, let's find the value of x by first equation.

$\sf \dashrightarrow 1.2x + 3y = 0$

$\sf \dashrightarrow 1.2x + 3(-2) = 0$

$\sf \dashrightarrow 1.2x - 6 = 0$

$\sf \dashrightarrow 1.2x = 6$

$\sf \dashrightarrow x = \dfrac{6}{1.2}$

$\sf \dashrightarrow x = 5$

Hence, the values of x and y are 5 and -2 respectively.