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deff fn [24]
3 years ago
15

Solve by using substitution-7x-2y=-13   and   x-2y=11

Mathematics
1 answer:
netineya [11]3 years ago
7 0
\left \{ {{-7x-2y=-13} \atop {x-2y=11}} \right. \\\\ \left \{ {{-7x-2y=-13} \atop {x=11+2y}} \right.\\\\
Substitute\ second\ equation\ into\ the\ first\ one:\\\\
-7(11+2y)-2y=-13\\
-77-14y-2y=-13\\
-77-16y=-13\ \ \ |Add\ 77\\
-16y= 64\ \ \ |Divide\ by\ -16\\
y=-4\\\\x=11+2y=11+2*(-4)=11-8=3\\\\ \left \{ {{y=-4} \atop {x=3}} \right.
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Aiden wrote a riddle: Five less than 1/5 times a number is the same as the sume of the number and 1/3. Find the number.
Brrunno [24]

The number is -6.67

<em><u>Solution:</u></em>

Let "n" be the number

From given,

\text{ Five less than 1/5 times a number } = \frac{1}{5}n - 5 = \frac{5}{n} - 5

\text{Sum of number and 1/3 } = n + \frac{1}{3} =\frac{3n+1}{3}

Given that,

Five less than 1/5 times a number is the same as the sum of the number and 1/3

Therefore, we get,

\frac{n}{5} - 5 = n + \frac{1}{3}\\\\Simplify\ the\ expression\\\\n - 25 = 5(n + \frac{1}{3})\\\\n - 25 = 5n + \frac{5}{3}\\\\n - 25 = \frac{15n + 5}{3}\\\\3n - 75 = 15n + 5\\\\12n = -80\\\\n = -6.67

Thus the number is -6.67

7 0
3 years ago
richard spends 30% of his monthly budget on rent. His total monthly is 3,000. How much does Ricard spend on rent
Alexeev081 [22]
He spends 900 on rent
6 0
3 years ago
Read 2 more answers
Stefan sells Jin a bicycle for $138 and a helmet for $18. The total cost for Jin is 130% of what
lys-0071 [83]

Answer:

1. $109.20 2. $46.80

Step-by-step explanation:

Doing the math, we find that 30% of 156 (138+18) is 46.80, which answers the second part of this problem. Plugging this value into the first part of the equation gives us what Stefan originally paid.

Good luck! Hope this helps!

5 0
2 years ago
Find x of the triangle
sukhopar [10]

Answer:

Step-by-step explanation:

altitude = sqrt(6*8) = 4*sqrt(3)

Use the Pythagorean Theorem to derive x

altitude^2 + 18^2 = x^2

48 + 18^2 = x^2

x^2 = 342

x = 3*sqrt(38)

x = 18.49

5 0
3 years ago
The graph below shows the amount of money left in the school’s desk fund, f, after d desks have been purchased. A graph titled D
natima [27]

Answer:

$110

Step-by-step explanation:

The computation is shown below:

Provided that

Number of desk purchased    Fund Left $

           0                                   700

           1                                    590

           2                                   480

           3                                   370

           4                                   260

           5                                   150

           6                                    40

Now the Fund decreased while purchasing is

= 5 desks - 2 desks

= 3 desks

i.e

= $480 - $150

= $330

Now the amount of money left for decreased the desk fund is

= \frac{Fund\ decreased }{number\ of\ desk\ decreased}

= \frac{\$330}{3\ desk}

= $110

3 0
3 years ago
Read 2 more answers
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