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pychu [463]
4 years ago
9

Solve 7x+3y=8 and 4x-y=-9 simultaneously

Mathematics
1 answer:
Jobisdone [24]4 years ago
5 0

Answer: x = -1 and y = 5

Step-by-step explanation:

7x + 3y = 8 ........................... equation 1

4x - y = - 9 ............................ equation 2

Solving the simultaneous linear equation by substitution method , make y the subject of the formula from equation 2 , we have

y = 4x + 9 ............................. equation 3

substitute y = 4x + 9 into equation 1 , we have;

7x + 3 ( 4x + 9 ) = 8

7x + 12x + 27 = 8

19x + 27 = 8

subtract 27 from both sides

19x = -19

divide through by 19

x = -1

substitute x = -1 into equation 3 , we have

y = 4 ( -1) + 9

y = -4 + 9

y = 5

Therefore :

x = -1 and y = 5

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Three Friends all have ages that are consecutive integers. The sum of their ages is 48. What is the age of the oldest friend?
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Consecutive integers = in this situation double-digit whole numbers So as there are 3 of them let's say 2 are 11 because that would be the highest consecutive number so 11+11= 22 and 48-22=26 so the three have the ages of 11,11,26 and the oldest would be 26 ;)
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3 years ago
12) Given f = {(-3,40),(-2,25),(-1,14),(0,7),(1,4),(2,5),(3,7)}
never [62]

Answer:

<em>Part a) </em>Domain of f : {-3, -2, -1, 0, 1, 2, 3}

<em>Part b) </em>Domain of g : {-1, 0, 1, 2, 3, 4}

<em>Part c)  </em>Domain of f+g = {-1, 0, 1, 2, 3}

<em>Part d) </em>Ordered Pairs of f-g = {(-1, 10), (0, 2), (1, -2), (2, 4), (3, 23)}

Step-by-step explanation:

<em>Part a) Determining the domain of f </em>

Given f = {(-3,40),(-2,25),(-1,14),(0,7),(1,4),(2,5),(3,7)}

Domain is the set of the input values of x which define the function. In other words, domain is the set of all the first elements of order pairs.

Domain of f : {-3, -2, -1, 0, 1, 2, 3}

<em>Part b) Determining the domain of g</em>

Given g= {(-1,4),(0,5),(1,6),(2,1),(3,-16),(4,-51)}

As domain is the set of the input values of x which define the function. In other words, domain is the set of all the first elements of order pairs.

Domain of g : {-1, 0, 1, 2, 3, 4}

<em>Part c) Determining the domain of f+g</em>

<em>When there is a sum of two functions f and g, then domain of f+g will be the intersection of their domains.</em>

<em>As,</em>

<em>      </em>Given f = {(-3,40),(-2,25),(-1,14),(0,7),(1,4),(2,5),(3,7)}

      Domain of f : {-3, -2, -1, 0, 1, 2, 3}

and,

      Given g= {(-1,4),(0,5),(1,6),(2,1),(3,-16),(4,-51)}

       Domain of g : {-1, 0, 1, 2, 3, 4}

<em>As</em> when <em>there is a sum of two functions f and g, then domain of f+g will be the intersection of their domains</em>

So, the domain of f+g = {-1, 0, 1, 2, 3}

<em>Part d) List the ordered pairs of f-g</em>

As

    f = {(-3,40),(-2,25),(-1,14),(0,7),(1,4),(2,5),(3,7)}

and

    g = {(-1,4),(0,5),(1,6),(2,1),(3,-16),(4,-51)}

For f - g, we must focus on subtracting the second (y) coordinates of both function that correspond to the same element in the domain (x)

(f - g)(x) = f(x) - g(x)

(f - g)(x) = f(-1) - g(-1)  = 14 - 4 = 10

(f - g)(x) = f(0) - g(0)  = 7 - 5 = 2

(f - g)(x) = f(1) - g(1)  = 4 - 6 = -2

(f - g)(x) = f(2) - g(2)  = 5 - 1 = 4

(f - g)(x) = f(3) - g(3)  = 7 - (-16) = 23

So,

Ordered Pairs of f-g = {(-1, 10), (0, 2), (1, -2), (2, 4), (3, 23)}

Keywords:  domain, function, f+g, f-g

Learn more about domain, and ordered pairs from brainly.com/question/11422136

#learnwithBrainly

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Answer: 150 would be the answer  hun

Step-by-step explanation:

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