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Oduvanchick [21]
2 years ago
12

Solve the system of equations. 10x+y=−20 y=2x2−4x−16 ( , ) and ( , )

Mathematics
2 answers:
Sladkaya [172]2 years ago
7 0
I will go about solving this using the elimination method.

First, convert the equations.

10x + y = -20
4x + y = -12

Second, find the easiest variable to get rid of and get rid of it!  (In this case, y)  We will subtract to get rid of y.

6x = -8

Third, you want to solve the equation.

6x = -8 (divide by 6)
x = -1 \frac{1}{3}

Fourth, solve for y by inserting the answer for x into one of the equations.

10(-1 \frac{1}{3}) + y = -20
-13 \frac{1}{3} + y = -20 (subtract -13 \frac{1}{3})
y = -6 \frac{2}{3}

The solution for this system of equations is (-1 \frac{1}{3}, -6 \frac{2}{3}).
nikdorinn [45]2 years ago
3 0

Answer:

(-2,0) and (-1,-10).

Step-by-step explanation:

We have been given a system of equations. We are asked to solve our given system of equations.

10x+y=-20...(1)

y=2x^2-4x-16...(1)

We will use substitution method to solve our given system. From equation (1) we will get,

y=-20-10x

Substituting this value in equation (1) we will get,

-20-10x=2x^2-4x-16

-20+20-10x=2x^2-4x-16+20

-10x=2x^2-4x+4

-10x+10x=2x^2-4x+10x+4

0=2x^2+6x+4

Now we will use quadratic formula to solve for x.

x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}

x=\frac{-6\pm \sqrt{6^2-4*2*4}}{2*2}

x=\frac{-6\pm \sqrt{36-32}}{4}

x=\frac{-6\pm \sqrt{4}}{4}

x=\frac{-6}{4}\pm \frac{\sqrt{4}}{4}

x=-1.5\pm \frac{2}{4}

x=-1.5\pm 0.5

x=-1.5-0.5\text{ or }-1.5+0.5

x=-2\text{ or }-1

Now to find y values we will substitute x=-2\text{ and }x=-1 in equation (1) as.

10(-2)+y=-20

-20+y=-20

-20+20+y=-20+20

y=0

Now, we will substitute x=-1 in equation (1) as.

10(-1)+y=-20

-10+y=-20

-10+10+y=-20+10

y=-10

Therefore, there are two solutions for our given system that are (-2,0) and (-1,-10).

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