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Solve the system of equation

Solve the system of equation-example-1
User PcnThird
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1 Answer

2 votes

Answer:

So the Point of intersection is (-4,-2)

Which is option A

Explanation:

The given system of equations is

-0.1x - 0.8y = 2 ...................(i)

0.6x - 0.5y = -1.4 ...................(ii)

Let us take equation (i) and use method of substitution for solving it

the equation (i) is

-0.1 x - 0.8y = 2

Adding 0.8y on both sides

-0.1 x + 0.8 y - 0.8 y = 2 + 0.8 y

-0.1 x = 2 + 0.8 y

Dividing both sides -0.1


(-0.1 x)/(-0.1)=(0.8 y)/(-0.1)+(2)/(-0.1)

x = -8 y - 20 ..........................(iii)

Now we will use this value and put it into equation (ii) to find the value of y

Equation (ii) is

0.6 x - 0.5 y = -1.4

Put value of x

0.6(-8 y - 20) - 0.5 y =-1.4

It becomes

-4.8 y - 12 - 0.5 y = -1.4

adding 12 on both sides

-4.8 y - 0.5 y - 12 + 12 = -1.4 + 12

it becomes by solving

-5.3 y = 10.6

Dividing both sides by -5.3


(-5.3*y)/(-5.3)=(10.6)/(-5.3)

So

y = -2

Now we have the value of y putting it in equation (iii)

Equation (iii) is

x = -8 y - 20

Putting value of y

x = -8*(-2) - 20

x = 16-20

x=-4

So the Point of intersection is (-4,-2)

User Daveaspinall
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