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3 years ago

The age of three sisters are consecutive integers. The sum of their ages is 45. Calculate their ages.

2 answers:

6 0

Consecutive means right after each other like 1, 2, 3, 4...so if the first sister is x old, then sister 2 is (x+1) old and sister 3 is (x+2) old. So make an equation that says x+(x+1)+(x+2)=45. Simplify and solve for x (get x alone.)

stiks02 [169]3 years ago

6 0

The first sister is 14 the second sister is 15 and the third sister is 16

45-3=42

42 divided by 3 equals 14

14+1=15+1=16

14+15+16=45

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1 year ago

Prove that if r is any rational number, then 3r2 − 2r + 4 is rational. The following properties may be used in your proof. Prope

ziro4ka [17]

Given:

Expression is

$3r^2-2r+4$

To prove:

If r is any rational number, then $3r^2-2r+4$ is rational.

Step-by-step explanation:

Property 1: Every integer is a rational number. It is Theorem 4.3.1.

Property 2: The sum of any two rational numbers is rational. It is Theorem 4.3.2.

Property 3: The product of any two rational numbers is rational. It is Exercise 15 in Section 4.3.

Let r be any rational number.

We have,

$3r^2-2r+4$

It can be written as

$3(r\times r)-2r+4$

Now,

3, -2 and 4 are rational numbers by property 1.

$r^2=r\times r$ is rational by Property 3.

$3r^2\text{ and }-2r$ are rational by Property 3.

$3r^2+(-2r)+4$ is rational by property 2.

So, $3r^2-2r+4$ is rational.

Hence proved.

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Answer:

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