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RSB [31]
3 years ago
10

X+y= -9 x+2y= -25 According to the system of equations above, what is the value of y?

Mathematics
1 answer:
Varvara68 [4.7K]3 years ago
6 0
Try this option:
if x+y=-9 is I (one)
and x+2y=-25 is II (two), then
if II-I, then (x+2y)-(x+y)=-25+9 ⇔ y=-16.
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0.075km, 7.6m, 77cm, 780mm from smallest to largest
Neko [114]

Answer:

77cm, 780mm, 7.6m, 0.075km

this is the best answer

7 0
3 years ago
If the product of x^2a-1/y^3b+4 and x^7b-4/y^10-a is x^24/y^19 find the value of a and b
lidiya [134]

Answer:

a = 4; b = 3

Step-by-step explanation:

For the question to make any sense, we need to add parentheses.

... x^(2a-1)/y^(3b+4) × x^(7b-4)/y^(10-a) = x^24/y^19

Equating exponents, we have ...

... (2a-1) + (7b-4) = 24 . . . . exponent of x in the product

... (3b+4) + (10 -a) = 19 . . . exponent of y in the product

Simplifying these two equations, we get

... 2a +7b = 29

... a -3b = -5

By Cramer's rule, ...

... a = (7·(-5) -(-3·29)/(7·1 -(-3·2)) = 52/13 = 4

... b = (29·1 -(-5·2))/13 = 39/13 = 3

_____

<em>More about Cramer's Rule</em>

If you have the linear equations ...

  • ax +by = c
  • dx +ey = f

The solutions for the variables x and y can be found directly from the equation coefficients as ...

... x = (bf -ec)/(bd -ea)

... y = (cd -fa)/(bd -ea) . . . . same denominator as for the first equation

Once you recognize the pattern in the products, the formula is not difficult to remember.

___

This is actually the Vedic math version of Cramer's rule. It differs from the usual presentation of Cramer's rule in that both numerator and denominator are negated. This makes the pattern of products easier to remember and gives exactly the same result.

6 0
3 years ago
Juan has a piano recital next month.last week he practiced for 8 hours in the morning and 7 hours in the afternoon. Each practic
valentina_108 [34]
Well if it was 8 hours in the morning and 7 in the evening per day of the week it would be 105 divided by 2 for the number of sessions would equal to 52.5 sessions. if it was just that amount of time from that whole week, it would be 15 hours divided by 2 which would give you 7.5... Did that help?
3 0
2 years ago
Read 2 more answers
What is the axis of symmetry?
jarptica [38.1K]

Answer:

2 or y=2

Step-by-step explanation:

You can find it by calculating -\frac{b}{2a}

- \frac{-20}{10} = 2

The axis of symmetry is 2

3 0
3 years ago
The official all-time high temperature in Osoyoos, B.C., was 43°C in July 1998. The official all-time low temperature was –21°C
lesantik [10]

Answer: 64°C

Step-by-step explanation:

Official all-time high temperature = 43°C

Official all-time low temperature = –21°C

The difference between the two temperatures will be calculated by subtracting the low temperature from the high temperature. This will be:

= 43°C - (-21°C)

= 43°C + 21°C

= 64°C

6 0
2 years ago
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