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2 years ago

-11 - (-7)= simplify

Mathematics

2 answers:

Inessa [10]2 years ago

8 0

-11-(-7)
-11+7
Your answer is -4

Galina-37 [17]2 years ago

8 0

Hai !
-11-(-7)
-11+4
-4---- the answer :3
Cheers, Irys :3

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Which expression can be used to solve 3/5 divide by 7/10

kramer

Answer:

$\frac{3}{5} *\frac{10}{7}$

= $\frac{30}{35} =\frac{6}{7}$

7 0

2 years ago

For which system of equations is (5, 3) the solution? A. 3x – 2y = 9 3x + 2y = 14 B. x – y = –2 4x – 3y = 11 C. –2x – y = –13 x

Alla [95]

The correct answer is:

D) $\left \{ {{2x-y=7} \atop {2x+7y=31}} \right.$ .

Explanation:

We solve each system to find the correct answer.

For A:
$\left \{ {{3x-2y=9} \atop {3x+2y=14}} \right.$

Since we have the coefficients of both variables the same, we will use elimination to solve this.

Since the coefficients of y are -2 and 2, we can add the equations to solve, since -2+2=0 and cancels the y variable:
$\left \{ {{3x-2y=9} \atop {+(3x+2y=14)}} \right. 
\\
\\6x=23$

Next we divide both sides by 6:
6x/6 = 23/6
x = 23/6

This is not the x-coordinate of the answer we are looking for, so A is not correct.

For B:
$\left \{ {{x-y=-2} \atop {4x-3y=11}} \right.$

For this equation, it will be easier to isolate a variable and use substitution, since the coefficient of both x and y in the first equation is 1:
x-y=-2

Add y to both sides:
x-y+y=-2+y
x=-2+y

We now substitute this in place of x in the second equation:
4x-3y=11
4(-2+y)-3y=11

Using the distributive property, we have:
4(-2)+4(y)-3y=11
-8+4y-3y=11

Combining like terms, we have:
-8+y=11

Add 8 to each side:
-8+y+8=11+8
y=19

This is not the y-coordinate of the answer we're looking for, so B is not correct.

For C:
Since the coefficient of x in the second equation is 1, we will use substitution again.

x+2y=-11

To isolate x, subtract 2y from each side:
x+2y-2y=-11-2y
x=-11-2y

Now substitute this in place of x in the first equation:
-2x-y=-13
-2(-11-2y)-y=-13

Using the distributive property, we have:
-2(-11)-2(-2y)-y=-13
22+4y-y=-13

Combining like terms:
22+3y=-13

Subtract 22 from each side:
22+3y-22=-13-22
3y=-35

Divide both sides by 3:
3y/3 = -35/3
y = -35/3

This is not the y-coordinate of the answer we're looking for, so C is not correct.

For D:
Since the coefficients of x are the same in each equation, we will use elimination. We have 2x in each equation; to eliminate this, we will subtract, since 2x-2x=0:

$\left \{ {{2x-y=7} \atop {-(2x+7y=31)}} \right. 
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\\-8y=-24$

Divide both sides by -8:
-8y/-8 = -24/-8
y=3

The y-coordinate is correct; next we check the x-coordinate Substitute the value for y into the first equation:
2x-y=7
2x-3=7

Add 3 to each side:
2x-3+3=7+3
2x=10

Divide each side by 2:
2x/2=10/2
x=5

This gives us the x- and y-coordinate we need, so D is the correct answer.

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2 years ago

F(x) = (4x–5)/6 Find the Inverse

noname [10]

Answer:

F^-1 (x) = 3x/2+5/4

Step-by-step explanation:

First, replace f(x) with y

Replace every x with a y and replace every y with an x .

Solve the equation from Step 2 for y

Replace y with f−1(x) f − 1 ( x )

Verify your work by checking that (f∘f−1)(x)=x ( f ∘ f − 1 ) ( x ) = x and (f−1∘f)(x)=x ( f − 1 ∘ f ) ( x ) = x are both true.

Hope this helps! Stay Safe!

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2 years ago

A rectangle has an area of 171 square meters. Its width is ten meters less than the length. Find the measures of the length and

9966 [12]

Step-by-step explanation:

The area of a rectangle is 171 m²

Let l is the length and b is the width of the rectangle

It width is 10 m less than the length. So,

b = l-10 ...(1)

Area of a rectangle is given by :

$A=l\times b\\\\171=l(l-10)\\\\l^2-10l=171\\\\l^2-10l-171=0\\\\l^2-19l+9l-171=0\\\\\text{taking common together}\\\\l(l-19)+9(l-19)=0\\\\(l-9)(l-19)=0$

l = 9 m or l = 19 m

If l = 9 m,

b = 9-10 = -1 m (can't be possible)

If l = 19 m

b = 19-10 = 9 m

So, the length an the breadth of the rectangle is 19 m and 9 m respectively.

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2 years ago

Explain how estimation helps you place the decimal point when multiplying 3.9 &5.3

kow [346]

3.9 and 5.3, when rounded off and mult. together, produce the product 20.
Thus, the decimal point must follow the first two digits of your answer, whether estimate or "exact."

3.9*5.3 = 20.67 by calculator.

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2 years ago