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solniwko [45]
2 years ago
7

Use the substitution method to determine the solution of the system of equations. y = -5x and 21x - 7y = 28

Mathematics
1 answer:
8_murik_8 [283]2 years ago
3 0

Answer:

x = 1/2   y = -5/2

Step-by-step explanation:

Since we already know an equation for y, we just need to plug it into the other equation.

21x - 7(-5x) = 28

21x + 35x = 28

56x = 28

x = 1/2

Now that we know x, we substitute it into the other equation, to find y.

y = -5x

y = -5(1/2)

= -5/2

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I need hlep its do to day
Taya2010 [7]

Answer:

x = -6/5

Step-by-step explanation:

distribute -4 on the left side of the equation first, then distribute 2 on the right side of the equation to get:

16x - 4 - 4x = 2x - 14 - 2

combine 'like terms':

12x - 4 = 2x - 16

subtract '2x' from each side to get:

10x - 4 = -16

add 4 to each side to get:

10x = -12

x = -12/10 or x = -6/5

3 0
2 years ago
8) BRAINLIEST AND 15 POINTS! PLS HELP ASAP
algol13

Answer:

a.) Between 0.5 and 3 seconds.

Step-by-step explanation:

So I just went ahead and graphed this quadratic on Desmos so you could have an idea of what this looks like. A negative quadratic, and we're trying to find when the graph's y-values are greater than 26.

If you look at the graph, you can easily see that the quadratic crosses y = 26 at x-values 0.5 and 3. And, you can see that the quadratic's graph is actually above y = 26 between these two values, 0.5 and 3.

Because we know that the quadratic's graph models the projectile's motion, we can conclude that the projectile will also be above 26 feet between 0.5 and 3 seconds.

So, the answer is a.) between 0.5 and 3 seconds.

4 0
3 years ago
An ordered pair of real numbers can be represented in a plane called the rectangular coordinate system or the ___________ plane
Ghella [55]
Coordinate plane is the answer
5 0
3 years ago
Please help........................
ivanzaharov [21]

The volume of a sphere is 4/3 * pi * r³ so substitute the values in

4/3 * pi * 2³

4/3 * pi * 8

32/3 * pi

The volume is either 32/3pi units³ or 33.49 units³ (they're the same value)

I hope this helps!

6 0
3 years ago
Kassie recorded the favorite sport of students at her school. She surveyed 800 students. How many more students chose Baseball t
lisov135 [29]

Answer:

40 more kids chose baseball over basketball.

Step-by-step explanation:

The best way to go about this is to use benchmark percentages.

For baseball, 25% of 800 people chose that, so we can do 800/4 to get 200, so 200 students chose baseball

For basketball, we could do 800/5 but that isn't mental math, so we can do 10% of 800 is 80 and 80*2=160. So 40 more kids chose baseball over basketball.

6 0
3 years ago
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