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LuckyWell [14K]
3 years ago
12

I need help on number 16 these instructions say to solve these equations by cross multiplying

Mathematics
1 answer:
Grace [21]3 years ago
8 0

Answer:

  15.  x = 4

  16.  a = 19

Step-by-step explanation:

"Cross multiply" essentially means "multiply both sides of the equation by the product of the denominators."

__

<h3>15.</h3>

  \dfrac{x}{6}=\dfrac{2}{3}\\\\3(x)=6(2)\qquad\text{"cross multiply"}\\\\\boxed{x=4}\qquad\text{divide by 3}

This is an example of a problem in which cross-multiplying introduces the need for an extra step: divide by 3. Had we simply multiplied by the denominator of the x-term, we would have been finished in one step:

  x = 6(2/3) = 4

That is, rather than multiplying by the <em>product of the denominators</em>, sometimes the problem can be solved more easily if you multiply by their <em>least common multiple</em>.

__

<h3>16.</h3>

  \dfrac{a+1}{a+5}=\dfrac{a-4}{a-1}\\\\(a-1)(a+1)=(a+5)(a-4)\qquad\text{"cross multiply"}\\\\a^2-1=a^2+a-20\qquad\text{simplify}\\\\\boxed{19=a}\qquad\text{add $20-a^2$}

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One serving of soybeans contains 14 grams of protein and 8 grams of fat. One serving of rice contains 4 grams of protein and 1/2
mina [271]

Answer: 1.8 servings of soybean and 1.2 servings rice will be needed.

Step-by-step explanation:

Let x be the number of soybeans and y be the number of rice.

Then , According to the question , we have

14x+4y=30\\\Rightarrow\ 7x+2y=15..................................(1)\\\\ 8x+\frac{1}{2}y = 15\\\Rightarrow\ 16x+y=30.............................(2)

Multiply 2 on both the sides of equation (2), we get

32x+2y=60................................(3)

Subtract equation (2) from equation (3), we get

25x=45\\\\\Rightarrow\ x=1.8

Put x = 1.8 in equation (2), we get

16x+y=30\\\\\Rightarrow\ y=30-16x\\=30-16(1.8)=1.2

Hence, 1.8 servings of soybean and 1.2 servings rice will be needed.

8 0
4 years ago
The width of a rectangle stage is 55% of its length. The stage is 120 feet long .What is the area?
saveliy_v [14]

Answer:

7920 square feet.

step -by- step explanation.

From the the question, the

Length, l= 120 feet.

Width, w= 55% of l

This implies that;

w=0.55×120=66 feet.

Area of rectangle is given by the relation ;

A =l \times w

By substitution,

A =120\times 66

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Therefore the area of the rectangular stage is 7920 square feet.

5 0
3 years ago
Help me with this question ​
enot [183]

Answer:

37.2

Step-by-step explanation:

when you turn the small triangle LMN to its right angle to cover the right angle of KLM, you find that they are similar triangles.

therefore the corresponding side lengths are at the same ratio.

LM/KM = MN/LN

LM = 24

MN = 13

we can get LN via Pythagoras of the small triangle

LN² + MN² = LM²

LN² + 13² = 24²

LN² = 24² - 13² = 576 - 169 = 407

LN = sqrt(407) = 20.174241

now back to our main problem

24/KM = 13/sqrt(407)

24×sqrt(407)/13 = KM = 37.2

4 0
3 years ago
Simplify using a table (6q+7)(2q+3)
Valentin [98]
<span> (6q+7)(2q+3)
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4 0
3 years ago
Read 2 more answers
Fill in the blanks to solve 50times 4
IgorLugansk [536]

Answer:

The answer is 200

Step-by-step explanation:

8 0
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