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Lady_Fox [76]
3 years ago
11

Para resolver un sistema de ecuaciones lineales 2x2 por el método de sustitución se debe tener en cuenta:

Mathematics
1 answer:
faltersainse [42]3 years ago
8 0

Answer:

El método de igualación consiste en despejar la misma incógnita en las dos ecuaciones y después igualar los resultados.

Los pasos a seguir son los siguientes:

sistema de ecuaciones

En primer lugar, elegimos la incógnita que deseamos despejar. En este caso, empezaré por la «x» y despejo la misma en ambas ecuaciones.

x+y=7; x=7-y

5x-2y=-7; 5x=2y-7

x=(2y-7)/5

Una vez hemos despejado, igualamos:

7-y = (2y-7)/5

5.( 7-y) = (2y -7)

35 -5y= +2y -7

42=7y

y=42/7=6

y=6

Por último, sustituimos el valor que hemos calculado despejando la otra incógnita en una de las ecuaciones iniciales.

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Stan's bike ride is 56.25 miles long.
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Ranger says the expression is not in its simplest form. He thinks the two terms need to be combined. Is Ranger right that 8x − 2
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5 0
4 years ago
Read 2 more answers
Compute the sales tax for the prices and rates given below. Price Tax Rate Tax $199 5% $4,750 6% $99.50 4.7% $19.88 6.9% $8.95 7
andrew11 [14]

Answer:

1. $9.95

2. $285.00

3. $4.68

4. $1.37

5. $0.64

6. $0.97

7. $22.86

8. $0.61

9. $2.14

10. $0.73

Step-by-step explanation:

Price                         Tax Rate                    Tax

1. $199                                5%                        = 199*0.05 = $9.95

2. $4750                             6%                         = 4750*0.06 = $285

3. $99.50                            4.7%                       = 99.50*0.047=$4.68

4. $19.88                            6.9%                        = 19.88* 0.069 =$1.37

5. $8.95                              7.2%                         = 8.95*0.072 =$0.64

6. $14.27                             6.8%                         = 14.27*0.068 =$0.97

7. $544.38                          4.2%                          =544.38*0.042 =$22.86

8. $7.49                               8.1%                           = 7.49*0.081=$0.61

9. $28.56                             7.5%                          =28.56*0.075 =$2.14

10 .$14.98                               4.9%                         = 14.98*0.049 =$0.73


Thank you.


4 0
4 years ago
Can i get some help with #5 please
Sidana [21]
 a = 6, is your answer.

Square both sides
<span><span><span>9=a−2<span>(6−a)(2a−3)</span>+3</span>9=a-2\sqrt{(6-a)(2a-3)}+3</span><span>9=a−2<span>√<span><span>​<span>(6−a)(2a−3)</span></span>​<span>​​</span></span></span>+3

</span></span>2 .Separate terms with roots from terms without roots
<span><span><span>9−a−3=−2<span>(6−a)(2a−3)</span></span>9-a-3=-2\sqrt{(6-a)(2a-3)}</span><span>9−a−3=−2<span>√<span><span>​<span>(6−a)(2a−3)
</span></span>​<span>​​</span></span></span></span></span>
3. Simplify <span><span><span>9−a−3</span>9-a-3</span><span>9−a−3</span></span> to <span><span><span>6−a</span>6-a</span><span>6−a
</span></span><span><span><span>6−a=−2<span>(6−a)(2a−3)</span></span>6-a=-2\sqrt{(6-a)(2a-3)}</span><span>6−a=−2<span>√<span><span>​<span>(6−a)(2a−3)
</span></span>​<span>​​</span></span></span></span></span>
4 .Square both sides
<span><span><span><span><span>(6−a)</span>2</span>=4(6−a)(2a−3)</span>{(6-a)}^{2}=4(6-a)(2a-3)</span><span><span><span>(6−a)</span><span><span>​2</span><span>​​</span></span></span>=4(6−a)(2a−3)

</span></span>5 .Expand
<span><span><span>36−12a+<span>a2</span>=48a−72−8<span>a2</span>+12a</span>36-12a+{a}^{2}=48a-72-8{a}^{2}+12a</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>=48a−72−8<span>a<span><span>​2</span><span>​​</span></span></span>+12a

</span></span>6. Simplify <span><span><span>48a−72−8<span>a2</span>+12a</span>48a-72-8{a}^{2}+12a</span><span>48a−72−8<span>a<span><span>​2</span><span>​​</span></span></span>+12a</span></span> to <span><span><span>60a−72−8<span>a2</span></span>60a-72-8{a}^{2}</span><span>60a−72−8<span>a<span><span>​2</span><span>​​</span></span></span></span></span>
<span><span><span>36−12a+<span>a2</span>=60a−72−8<span>a2</span></span>36-12a+{a}^{2}=60a-72-8{a}^{2}</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>=60a−72−8<span>a<span><span>​2
</span><span>​​</span></span></span></span></span>
7. Move all terms to one side
<span><span><span>36−12a+<span>a2</span>−60a+72+8<span>a2</span>=0</span>36-12a+{a}^{2}-60a+72+8{a}^{2}=0</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>−60a+72+8<span>a<span><span>​2</span><span>​​</span></span></span>=0

</span></span>8. Simplify <span><span><span>36−12a+<span>a2</span>−60a+72+8<span>a2</span></span>36-12a+{a}^{2}-60a+72+8{a}^{2}</span><span>36−12a+<span>a<span><span>​2</span><span>​​</span></span></span>−60a+72+8<span>a<span><span>​2</span><span>​​</span></span></span></span></span> to <span><span><span>36−72a+9<span>a2</span>+72</span>36-72a+9{a}^{2}+72</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72</span></span>
<span><span><span>36−72a+9<span>a2</span>+72=0</span>36-72a+9{a}^{2}+72=0</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72=0

</span></span>9 .Simplify <span><span><span>36−72a+9<span>a2</span>+72</span>36-72a+9{a}^{2}+72</span><span>36−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+72</span></span> to <span><span><span>−72a+9<span>a2</span>+108</span>-72a+9{a}^{2}+108</span><span>−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+108</span></span>
<span><span><span>−72a+9<span>a2</span>+108=0</span>-72a+9{a}^{2}+108=0</span><span>−72a+9<span>a<span><span>​2</span><span>​​</span></span></span>+108=0

</span></span>10.Factor out the common term <span><span>99</span>9</span>
<span><span><span>−9(8a−<span>a2</span>−12)=0</span>-9(8a-{a}^{2}-12)=0</span><span>−9(8a−<span>a<span><span>​2</span><span>​​</span></span></span>−12)=0

</span></span>11. Factor out the negative sign
<span><span><span>−9×−(<span>a2</span>−8a+12)=0</span>-9\times -({a}^{2}-8a+12)=0</span><span>−9×−(<span>a<span><span>​2</span><span>​​</span></span></span>−8a+12)=0

</span></span>12. Divide both sides by <span><span><span>−9</span>-9</span><span>−9</span></span>
<span><span><span>−<span>a2</span>+8a−12=0</span>-{a}^{2}+8a-12=0</span><span>−<span>a<span><span>​2</span><span>​​</span></span></span>+8a−12=0

</span></span>13. Multiply both sides by <span><span><span>−1</span>-1</span><span>−1</span></span>
<span><span><span><span>a2</span>−8a+12=0</span>{a}^{2}-8a+12=0</span><span><span>a<span><span>​2</span><span>​​</span></span></span>−8a+12=0

</span></span>14. Factor <span><span><span><span>a2</span>−8a+12</span>{a}^{2}-8a+12</span><span><span>a<span><span>​2</span><span>​​</span></span></span>−8a+12</span></span>
<span><span><span>(a−6)(a−2)=0</span>(a-6)(a-2)=0</span><span>(a−6)(a−2)=0

</span></span>15. Solve for <span><span>aa</span>a</span>
<span><span><span>a=6,2</span>a=6,2</span><span>a=6,2

</span></span>16 Check solution
When <span><span><span>a=2</span>a=2</span><span>a=2</span></span>, the original equation <span><span><span>−3=<span>6−a</span>−<span>2a−3</span></span>-3=\sqrt{6-a}-\sqrt{2a-3}</span><span>−3=<span>√<span><span>​<span>6−a</span></span>​<span>​​</span></span></span>−<span>√<span><span>​<span>2a−3</span></span>​<span>​​</span></span></span></span></span> does not hold true.
We will drop <span><span><span>a=2</span>a=2</span><span>a=2</span></span> from the solution set.

17. Therefore,
<span><span><span>a=6</span></span><span /></span>


5 0
3 years ago
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