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Select the correct solutions for the system of equations:5x +y= -10y= 2^2 - 2x - 8

Select the correct solutions for the system of equations:5x +y= -10y= 2^2 - 2x - 8-example-1
User Bydsky
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1 Answer

10 votes
10 votes

Given:


5x+y=-10
y=x^2-2x-8

We can solve for the value of x through substitution.

We will substitute the value of y from the second equation, to the first equation.


5x+y=-10
5x+(x^2-2x-8)=-10
5x+x^2-2x=-10+8
x^2+3x=-2
x^2+3x+2=0

We then get the factors of this equation.

(x + 1)(x + 2) = 0

Next, we will solve for the value of x.


x+1=0
x=-1
x+2=0
x=-2

With these two values of x, we can now find the values of y through substituting the values of x to either equations.

Using the first equation, given that:

x = -1

x = -2


x=-1
5x+y=-10
5(-1)+y=-10
-5+y=-10
y=-10+5
y=-5

Therefore, this will give us a solution of (-1, -5).

Next,


x=-2
5x+y=-10
5(-2)+y=-10
-10+y=-10
y=-10+10
y=0

And this will give us a solution of (-2, 0).

Therefore, all the possible solutions for this system of equations are (-1, -5) and (-2, 0).

User Thalatta
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