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2 years ago

Can somebody help me please

Mathematics

1 answer:

serious [3.7K]2 years ago

8 0

Answer:

-7 and 21

Step-by-step explanation:

y-2y=7 (sub x=7 to the equation)

-y=7

y=-7 (not sure of its correct)

if y=-7,

x-2(-7)=7 (sub y=-7 into equation)

x-14=7

X=7+14

X=21

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7. Jennifer is 6 years older than Sue. In 4 years, she will be twice as old as Sue was 5 years ago. Find their ages

makvit [3.9K]

Answer: Sue is 20 and Jennifer is 26

Step-by-step explanation:

Let's say that J=Jennifer's age now and S=Sue's age now.

We know that:

J=S+6

Because Jennifer is 6 years older than Sue.

We also know that when Jennifer is 4 years older (J+4), she will be twice as old as Sue was 5 years from now (S-5).

So we get the following equation from that information:

J+4=2(S-5)

So we have the two equations:

J+4=2(S-5)

J=S+6

Let's substitute J=S+6 into the first equation (note that RHS means Right Hand Sie and LHS means Left Hand Side):

(S+6)+4=2(S-5)

S+10=2S-10 [Add 6+4 on the RHS, and distribute on the LHS]

S=2S-20 [Subtract 10 from both sides]

-S=-20 [Subtract 2S from both sides]

S=20 [Divide both sides by -1]

So we know S, which is Sue's age, is 20. So Sue is no 20 years old.

Finding Jennifer's age now is simple. We know Jennifer is 6 years older than Sue, and Sue is 20, so Jennifer is 26 years old.

4 0

2 years ago

Car X weighs 136 pounds more than car Z. Car Y weighs 117 pounds more than car Z. The total weight of all three cars is 9439 pou

Aleksandr [31]

Let x, y and z denote the weighs of car X, car Y and car Z, respectively.

We know that car X weighs 136 more than car Z, this can be express by the equation:

$x=z+136$

We also know that Y weighs 117 pounds more than car Z, this can be express as:

$y=z+117$

Finally, we know that the total weight of all the cars is 9439, then we have:

$x+y+z=9439$

Hence, we have the system of the equations:

$\begin{gathered} x=z+136 \\ y=z+117 \\ z+y+z=9439 \end{gathered}$

To solve the system we can plug the values of x and y, given in the first two equations, in the last equation; then we have:

$\begin{gathered} z+136+z+117+z=9439 \\ 3z=9439-136-117 \\ 3z=9186 \\ z=\frac{9186}{3} \\ z=3062 \end{gathered}$

Now that we have the value of z we plug it in the first two equations to find x and y:

$\begin{gathered} x=3062+136=3198 \\ y=3062+117=3179 \end{gathered}$

Therefore, car X weighs 3198 pound, car Y weighs 3179 pounds and car Z weighs 3062 pounds.

4 0

1 year ago

If and , find . A. B. C. D.

trapecia [35]

Answer: option D. 2x^2 + (3/2)x - 5

Explanation:

1) polynomials given:

f(x) = x/2 - 2 and g(x) = 2x^2 + x - 3

2) question: find (f + g) (x)

That means that f(x) + g(x), so you have to add up the two polynomials given.

3) x/2 - 2 + 2x^2 + x - 3

4) Combine like terms:

a) terms with x^2: you only have 2x^2, so it is not combined with other term.

b) terms with x: x/2 + x

that is a sum of fractions: x/2 + x = [x + 2x] / 2 = 3x / 2 = (3/2)x

c) constant terms: - 2 + (-3) = - 2 - 3 = - 5

5) Result: 2x^2 + (3/2)x - 5

That is the option d.

4 0

2 years ago

A square has a side of 6.25 feet. What is the area in square feet? Round to the correct significant digits.

Hunter-Best [27]

The solution to this question is 39.0625.

This is because you will need to multiply the width by height. As this is in square feet it will be irrespective of which two sides we choose.

The calculation that will need to be done is the following :

6.25ft X 6.25ft which will equal 39.0625.

6.25 has three significant digits so rounding 39.0625 off to three significant digits is 39.1 square feet

7 0

2 years ago

An English muffin and two fried eggs contain 330 calories. Three English muffins and

nalin [4]

Answer:

m+2e=330

3m+1e=515

use simultaneous formula to get

m=37

e=146.5

3 0

2 years ago