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4 years ago

Please help!posted picture of problem

Mathematics

2 answers:

svp [43]4 years ago

6 0

D. Multiply the top equation by 3 and the bottom equation by 4

IRISSAK [1]4 years ago

3 0

Option D is the correct answer.

Given equations are:

4x - 2y = 7
3x - 3y = 15

Multiplying 1st equation by 3 and second equation by 4, we get:

12x - 6y = 21
12x - 12y = 60

Now subtracting the equations will eliminate x from the equations, leaving y as the only variable.

You might be interested in

How many different perfect cubes are among the positive actors of 2021^2021

9966 [12]

Answer:

hope this helps :D

Step-by-step explanation:

Perfect cube factors:

If a number is a perfect cube, then the power of the prime factors should be divisible by 3.

Example 1:Find the number of factors of293655118 that are perfect cube?

Solution: If a number is a perfect cube, then the power of the prime factors should be divisible by 3. Hence perfect cube factors must have

2(0 or 3 or 6or 9)—– 4 factors

3(0 or 3 or 6) —– 3 factors

5(0 or 3)——- 2 factors

11(0 or 3 or 6 )— 3 factors

Hence, the total number of factors which are perfect cube 4x3x2x3=72

Perfect square and perfect cube

If a number is both perfect square and perfect cube then the powers of prime factors must be divisible by 6.

Example 2: How many factors of 293655118 are both perfect square and perfect cube?

Solution: If a number is both perfect square and perfect cube then the powers of prime factors must be divisible by 6.Hence both perfect square and perfect cube must have

2(0 or 6)—– 2 factors

3(0 or 6) —– 2 factors

5(0)——- 1 factor

11(0 or 6)— 2 factors

Hence total number of such factors are 2x2x1x2=8

Example 3: How many factors of293655118are either perfect squares or perfect cubes but not both?

Solution:

Let A denotes set of numbers, which are perfect squares.

If a number is a perfect square, then the power of the prime factors should be divisible by 2. Hence perfect square factors must have

2(0 or 2 or 4 or 6 or 8)—– 5 factors

3(0 or 2 or 4 or 6) —– 4 factors

5(0 or 2or 4 )——- 3 factors

11(0 or 2or 4 or6 or 8 )— 5 factors

Hence, the total number of factors which are perfect square i.e. n(A)=5x4x3x5=300

Let B denotes set of numbers, which are perfect cubes

If a number is a perfect cube, then the power of the prime factors should be divisible by 3. Hence perfect cube factors must have

2(0 or 3 or 6or 9)—– 4 factors

3(0 or 3 or 6) —– 3 factors

5(0 or 3)——- 2 factors

11(0 or 3 or 6 )— 3 factors

Hence, the total number of factors which are perfect cube i.e. n(B)=4x3x2x3=72

If a number is both perfect square and perfect cube then the powers of prime factors must be divisible by 6.Hence both perfect square and perfect cube must have

2(0 or 6)—– 2 factors

3(0 or 6) —– 2 factors

5(0)——- 1 factor

11(0 or 6)— 2 factors

Hence total number of such factors are i.e.n(A∩B)=2x2x1x2=8

We are asked to calculate which are either perfect square or perfect cubes i.e.

n(A U B )= n(A) + n(B) – n(A∩B)

=300+72 – 8

=364

Hence required number of factors is 364.

8 0

3 years ago

Will has 20 pounds of apples he makes to back to apple sauce that he's 4 pounds each one back to apple butter that use a 6 pound

Ulleksa [173]

Answer:

The equation representing pounds of apples will has left $x=20-4-6-3$ .

Will has left with 7 pounds of apples.

Step-by-step explanation:

Given:

Total pounds of apple = 20 pounds.

Pounds of apple used for apple sauce = 4 pounds

Pounds of apple used for apple butter = 6 pounds

Pounds of apple used for making juice = 3 pounds

We need to write the equation to represent pounds of apples will has left.

Solution:

Let us assume pounds of apples will has left be 'x'.

So we can say that;

pounds of apples will has left can be calculated by subtracting Pounds of apple used for apple sauce and Pounds of apple used for apple butter and Pounds of apple used for making juice from Total pounds of apple.

framing in equation form we get;

$x=20-4-6-3$

Hence The equation representing pounds of apples will has left $x=20-4-6-3$ .

On Solving the above equation we get;

$x=7\ pounds$

Hence Will has left with 7 pounds of apples.

4 0

3 years ago

A pet store has 6 tanks of fish. Each tank has c fish. Using c , write an expression for the total number of fish in the store.

Elanso [62]

Answer:

6xc

Step-by-step explanation:

8 0

3 years ago

Please help me out with this :)

Misha Larkins [42]

Answer:

x = 1

Step-by-step explanation:

Given that y varies directly with x then the equation relating them is

y = kx ← k is the constant of variation

To find k use the condition y = 12 when x = - 2, then

k = $\frac{y}{x}$ = $\frac{12}{-2}$ = - 6, thus

y = - 6x ← equation of variation

When y = - 6, then

- 6 = - 6x ( divide both sides by - 6 )

x = 1

8 0

4 years ago

Twice the sum of a number plus 4 is 26. Find the number

telo118 [61]

2(x+4)=26
2x+8=26
2x=14
X=7

8 0

3 years ago