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Rudiy27
3 years ago
9

21 = 4x - 9 - x what is x?

Mathematics
2 answers:
alexgriva [62]3 years ago
6 0

Answer:

x = 10

Step-by-step explanation:

Given

21 = 4x - 9 - x, that is

21 = 3x - 9 ( add 9 to both sides )

30 = 3x ( divide both sides by 3 )

10 = x

IrinaVladis [17]3 years ago
4 0

Answer:

x = 10

Step-by-step explanation:

21 = 4x - 9 - x

21 = 3x - 9

30 = 3x

10 = x

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Mrs. Kellen's most recent math test consisted of 50 questions. Some of the questions were worth two points and the rest of the q
WARRIOR [948]

Answer:

The answer to your question is: 35 questions worth 2 points and 15 questions worth 3 points.

Step-by-step explanation:

Data

Number of questions = 50

Total points = 115

x = questions worth 2 points

y = questions worth 3 points

Process

write to equations

(1)  ---------------    x + y = 50

(2) --------------    2x + 3y = 115

Solve them by substitution

           x = 50 - y

         2 (50 - y) + 3y = 115

          100 - 2y + 3y = 115

           3y -2 y = 115 - 100

                     y = 15

           x = 50 - 15

            x = 35

7 0
3 years ago
The following table shows the length and width of two rectangles:
zhannawk [14.2K]

Answer:

10x - 8 or 2( 5x - 4)

Step-by-step explanation:

Perimeter of a rectangle = 2( Length + Width)

<u>Rectangle A </u>

Length = x + 8,

Width  = x - 1

Perimeter_A = 2((x + 8) + ( x - 1))\\\\

                 = 2(x + 8 + x - 1) \\\\= 2(2x + 7)\\\\=4x + 14

<u>Rectangle B</u>

Length = 4x + 5

Width = 3x - 2

Perimeter _B= 2((4x + 5) + (3x-2))\\\\

                 =2(4x + 5 + 3x - 2)\\\\=2(7x + 3)\\\\=14x + 6

Perimeter_B - Perimeter_A = (14x +6)-(4x + 14) \\\\

                                       =14x + 6 - 4x - 14\\\\=10x -8\\\\or \\\\=2(5x - 4)

4 0
3 years ago
The formula for the surface area of a rectangular prism with a square base is SA=2s2+4shSA=2s2+4sh. What is the surface area of
Ivanshal [37]
This is the concept of algebra, given that the formula for the surface area of the prism is modeled by the expression SA=2s²+4sh , the surface area of the prism when s=3 and h=5 will be found by substituting the values in our expression as follows;
SA=2(3)²+4×3×5
SA=2(9)+60
SA=18+60
SA=78 sq. units
The answer is 78 sq. units

4 0
3 years ago
Read 2 more answers
Simplify 5 – 2y + (-8y) + 5.5.
zavuch27 [327]

Answer:

-10y + 10.5

Step-by-step explanation:

5 - 2y + (-8y) + 5.5

5 - 2y - 8y +5.5

-10y + 10.5

3 0
2 years ago
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Please help me, my teacher said that only 3 of them are right. so please get three right. please. The second file attached is th
iren [92.7K]

Answer:

What are you supposed to do

Step-by-step explanation:

4 0
3 years ago
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