the ratio of boys to girls at the movie is 4:7. If there are 21 girls, how many boys are at the movie?

Answers

Answer 1
Answer: boys:girls=4:7\n\ngirls=21\n\ntherefore\n\nboys:21=4:7\n\n(boys)/(21)=(4)/(7)\ \  \ \ \ |cross\ myltiply\n\n7\ boys=4*21\n\n7boys=84\ \ \ \ \ |divide\ both\ sides\ by\ 7\n\nboys=84:7\n\n\boxed{boys=12}
Answer 2
Answer: 7x=21\nx=3\n\n4x=4\cdot3=\boxed{12}

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What is a trick for multiplying 9`s

Answers

A trick that is good for multiplying 9's is, remember that each time the tens digit changes the number in the ones spaces minuses 1. If you don't understand what I am saying look at the following:- 

9
18
27
36
45
54
63
72
81

See the pattern? In the tens place you need to add 1 and in the tens place you need to subtract by 1.

Hope I helped ya!! xD
 This works for 9 times 1 through 9 times 10. You can take the number that is times 9 and and minis the number by one. Then you think about what number plus the first number ( the number that is times 9 and and minis the number by one) equals 9 and that number goes in the tens place. If you don't understand then look at this:
9×1=09
9×2=18
9×3=27
9×4=36
9×5=45
9×6=54
9×7=63
9×8=72
9×9=81
9×10=90

How do I solve 7 1/8÷4 3/4

Answers

Find Improper Fractions. Flip The Second Fraction. Divide. Simplify. Hope This Helps! :D
the answer is 1 76/152

7 1/8= 57/8

4 3/4= 19/4


57/8 * 4/19 (reciprocal)


answer is 228/152


change into a mix number which is 1 76/152

Kai wrote the number 85 on the board is 85 prime or composite?

Answers

Composite because prime can only be multiplied by itself but 85 can be multiplied by 5
The answer to is 85 prime or composite is composite

15. Tell whether the lines for each pair of equations are parallel perpendicular or neither Y=-3x+7
-2x+6y=3
16. Tell whether the lines for each pair of equations are parallel perpendicular or neither
Y=-1/5x+6
-2x+10y= 5

Answers

Answer:

15. The lines are perpendicular.

16. The lines are neither perpendicular nor parallel.

Step-by-step explanation:

15. The given lines are

Y=-3x+7 & -2x+6y=3 or, 6y = 3 + 2x or, y = 0.5 + (x)/(3).

The slope of the first line is -3 and the slope of the second line is (1)/(3)[Comparing with the standard form of equation of straight line y = mx + c, where m is the slope of the straight line].

Two straight lines will said to be perpendicular to each other, if the product of its slopes will be equal to -1.

Since, -3 * (1)/(3) = -1, the equations are perpendicular with respect to each other.

16. The lines are y = -(x)/(5) + 6 and -2x + 10y = 5 or, 10y = 5 + 2x or, y = 0.5 + (x)/(5).

As per the question number 15, it is clear that these equations are not perpendicular.

Here, the slope of the first one is (-1)/(5) and the slope of the second one is (1)/(5).

The values are same with different sign. Hence, these equations are not parallel too.

Solve -0.5(–2x+8) – 8 = 8.​

Answers

Answer:

x = 20

Step-by-step explanation:

Firstly, we have to distribute: (-0.5 * -2x) and (-0.5 * 8) -8 = 8

1x - 4 - 8 = 8

Next collect like terms:   1x - 12 = 8

Isolate x to get the value of x: Add 12 to both sides

1x = 20

So x = 20

Answer:x=20

Step-by-step explanation: first you distribute the value outside of the parentheses

-0.5*2x= 1x

-0.5*8=-4

it then becomes

x-4-8=8

combine -4 and -8

x-12=8

add the 12 over

x=20

Question 1 (1 point)Select all solutions to the equation.
3x – y=10
Only (4,-2)
Only (3, 1)
Both (4, -2) and (3, 1)
Neither

Answers

The answer is Neither