Mathematics, 28.01.2020 04:31 sophiat17

Can someone me solve these systems using elimination? i have a hard time with these.
8x-6y=-20
-16x+17y=30
and then..
-4y-11x=36
20= -10x-10y
show the steps so i can learn too. you!

Answers: 1

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Answer from: breanastone14

Question 1:

For this case we must solve the following system of equations by the method of elimination:

$8x-6y=-20\\-16x+17y=30$

We multiply the first equation by 2:

16x-12y = -40

We have the equivalent system:

$16x-12y = -40\\-16x + 17y = 30$

We add the equations:

5y = -10

We divide between 5 on both sides of the equation:

$y = - \frac {10} {5}\\y = -2$

We find the value of the variable "x":

$8x-6 (-2) = - 20\\8x + 12 = -20\\8x = -20-12\\8x = -32$

We divide by 8 on both sides of the equation:

$x = - \frac {32} {8}\\x = -4$

Thus, the solution of the system is:

(x, y): (- 4, -2)

Question 2:

For this case we must solve the following system of equations by the method of elimination:

$-4y-11x = 36\\20 = -10x-10y$

We multiply the first equation by 10:

-40y-110x = 360

We multiply the second equation by -4:

40y + 40x = -80

We have the equivalent system:

$-40y-110x = 360\\40y + 40x = -80$

We add the equations: -70x = 280

We divide by -70 on both sides of the equation:

$x = \frac {280} {- 70}\\x = -4$

We find the value of the variable "y":

$-4y-11 (-4) = 36\\-4y + 44 = 36\\-4y = 36-44\\-4y = -8$

We divide between -4 on both sides of the equation:

$y = - \frac {8} {- 4}\\y = 2$

Thus, the solution of the system is:

(x, y): (- 4,2)

Answer from: Quest

( - 4 , -7 )

all the lines must parallel

step-by-step explanation:

coordinates of c = ( - 1 , 2 )

3 units left = ( -4 , 2 )

9 units down = ( - 4 , 11 )

Answer from: Quest

1. sometimes

2. never

3 .08c = 7.50+.05c 250 pages

step-by-step explanation:

1. sometimes

the theoretical probability of rolling a 1 is 1/6. perhaps you got really lucky and never rolled a 1 in those 60 times. your experimental probability is 0. or perhaps you rolled a 1 20 times. your experimental probability is 20/60 is 1/3. it really just depends on how you rolled in that experiment.

2. never

the probability of the event occurring is 1. that is being 100 % sure it will happen. that is the maximum amount of confidence we have.

3. no customer card cost: .08 times number of pages

customer card cost: 7.50 + .05 times number of pages

we want to find when it costs the same amount, so we will set these equal

let c = number of pages

.08c = 7.50+.05c

subtract .05c from each side

.08c-.05c = 7.5+.05c-.05c

.03c=7.5

divide each side by .03

.03c/.03 = 7.5/03

c =250

the cost is the same at 250 pages

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Can someone me solve these systems using elimination? i have a hard time with these.
8x-6y=-...