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Greeley [361]
3 years ago
15

Solve the system by substitution. -Y = x -7x – 5y = –20

Mathematics
1 answer:
GaryK [48]3 years ago
5 0

Answer:

x=10\\y=-10\\

(10,-10)

Step-by-step explanation:

-y=x

-7x-5y=-20

Substitute -y for x in the second equation:

-7(-y)-5y=-20

Multiply:

7y-5y=-20

Combine like terms:

2y=-20

Divide both sides of the equation by the coefficient of y, which is 2:

y=-10

Now, substitute -10 for y in the first equation:

-(-10)=x

Multiply:

x=10

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F - 3/4=5/6. Please answer soon thanks
ad-work [718]
F - 3/4 = 5/6
Add 3/4 to both sides to get
F = 5/6 + 3/4 = 19/12
5 0
3 years ago
There were 3 apple, 1 mixed fruit, 2 grape, and 4 tropical fruit juice boxes in the cooler at the picnic. What is the probabilit
goldenfox [79]

There are  10  juice boxes in the cooler altogether.
2  of them are grape.

The first time Jill pulls one out with her eyes closed,
the probability that it's a grape is

                                         2 / 10 .

If that try is successful, then there are  9  boxes left in the cooler,
and one of them is grape.

If she already has one grape, and reaches in again with her eyes
closed, the probability of pulling out the second grape is

                                        1 / 9 .

The probability of both events happening in two tries is

                           (2/10) x (1/9) = 2/90 = 1/45  =  (2 and 2/9) percent .

6 0
4 years ago
Read 2 more answers
Use mental math to solve the equation w - (-3) = 7 please help
tester [92]

w-(-3)=7

Pretend that there is a -1 in front of the bracket

w-1(-3)=7

Mutiply the bracket by -1

(-1)(-3)=3

w+3=7

Move +3 to the other side. Sign changes from +3 to -3.

w+3-3=7-3

w=4

Answer: w=4

8 0
3 years ago
1- un tinaco se llena en 8 horas utilizando 4 llaves. en cuanto tiempo se llenara con 7 llaves?
svetoff [14.1K]

Answer: 4.6 horas.

Step-by-step explanation:

Podemos calcular el tiempo necesario por una llave:

si sabemos que se llena en 8 horas con 4 llaves, entonces una sola llave va a tardar 4 veces 8 horas en llenar el tinaco, es decir, una sola llave tarda:

4*8h = 32 horas

ahora, si usamos 7 llaves, el tiempo necesario va a ser un septimo de eso:

(32 h por llave)/(7 llaves) = 32/7 horas = 4.6 horas.

4 0
3 years ago
Solve the quadratic equation 6x^2-13x-28=0 by factoring.
mixer [17]

First step to factor the trinomial, multiply the constant -28 with the leading coefficient 6.

So, -28 * 6 = - 168.

Next step is to breakdown -168 into two multiples so that their addition will result the coefficient of w= - 13.

So, -168 = -21 * 8.

And addition of - 21 and 8 will give - 13.

So, next step is to replace -13x with -21x + 8. Therefore,

6x² - 21x + 8x - 28 =0

(6x² - 21x) + (8x - 28 )=0 Make the group of two terms.

3x (2x - 7) + 4 (2x - 7) = 0 Take out the common factor from each group.

(2x - 7)(3x + 4) = 0 Again take out the common factor (2x -7).

So, 2x - 7 =0, 3x + 4 = 0 Set both the factor equal to 0.

2x = 7 , 3x = -4

So, x= \frac{7}{2} , -\frac{4}{3}

Hope this helps you !

6 0
3 years ago
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