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Lyrx [107]
3 years ago
12

Betty is three times as old as her son now. In 12 years, Betty's age will be three years less than twice her son's age. How old

is Betty's son now?
Mathematics
1 answer:
laiz [17]3 years ago
3 0

Answer:

Betty is 27. Her son is 9.

Step-by-step explanation:

We will use b to represent Betty's age. We will use s to represent her son's age.

This year:

b = 3s

In 12 years' time:

b + 12 = 2(s + 12) - 3

b + 12 = 2s + 24 - 3

b + 12 = 2s + 21

b = 2s + 9

We know that b = 3s, so we can substitute this value into our equation.

3s = 2s + 9

s = 9

b = 3 x 9

b = 27

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Create an equation to solve for x using the trapezoid midsegment formula:
Serggg [28]

Answer:

Equation for x:    3x - 6 = \frac{2x - 1 + 25}{2}

x = 9

CD = 17

GH = 21

Step-by-step explanation:

The midsegment formula for a trapezoid is

GH = \frac{CD + FE}{2}

3x - 6 = \frac{2x - 1 + 25}{2}

6x - 12 = 2x + 24

4x = 36

x = 9

CD = 2x - 1 = 2(9) - 1 = 18 - 1 = 17

GH = 3x - 6 = 3(9) - 6 = 3 = 27 - 6 = 21

4 0
3 years ago
Find an equation of the circle that satisfies the given conditions.
hodyreva [135]
The equation of a circle:
(x-h)^2+(y-k)^2=r^2
(h,k) - the coordinates of the centre
r - the radius

The midpoint of the diameter is the centre of a circle.
The coordinates of the midpoint:
(\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2})
(x₁,y₁), (x₂,y₂) - the coordinates of endpoints

P(-1,1) \\
x_1=-1 \\ y_1=1 \\ \\ Q(5,9) \\ x_2=5 \\ y_2=9 \\ \\
\frac{x_1+x_2}{2}=\frac{-1+5}{2}=\frac{4}{2}=2 \\ \frac{y_1+y_2}{2}=\frac{1+9}{2}=\frac{10}{2}=5

The centre of the circle is (2,5).

The radius is the distance between an endpoint of the diameter and the centre.
The formula for distance:
d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}

(-1,1) \\ x_1=-1 \\ y_1=1 \\ \\ (2,5) \\ x_2=2 \\ y_2=5 \\ \\ d=\sqrt{(2-(-1))^2+(5-1)^2}=\sqrt{3^2+4^2}=\sqrt{9+16}=\sqrt{25}=5

The radius is 5.

(x-2)^2+(y-5)^2=5^2 \\
\boxed{(x-2)^2+(y-5)^2=25}
4 0
3 years ago
No links, find the length of X in inches
krek1111 [17]

Answer:

107 inches

Step-by-step explanation:

28+45+x=180

x=180-28+45

x=180-73

x=107

7 0
3 years ago
Write the slope intercept form of a line that passes<br> through (3, -2) and is 1 to y = x + 3.
zhuklara [117]

Answer:12

Step-by-step explanation:

8 0
4 years ago
If a car averages 21.8 miles per gallon, how many miles will it travel on 16 gallons of gas?
asambeis [7]

Answer: 348.8 miles on 16 gallons of gas

Step-by-step explanation:

Make the following proportion:

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Since the car consumes gas at the same rate and only the amount of gas is changed, these two fractions must be equivalent. If the rate at which the car consumes gas changes, it would be different.

Use basic algebraic skills and you should get 348.8 miles.

7 0
2 years ago
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