Question

Please help
Solve: 15 decreased by twice a number is 21. 


A.-3


B.3


C.18


D.-18

Answer 1

Use the statement to get an equation. Then solve the equation.

Let the number be x.

15 decreased by twice a number is 21.

15 - 2x = 21

Solve 15 - 2x = 21 for x.

Answer 2

-3 @mathstudent55

Answer 3

Correct. The answer is A.

Answer 4

Can you help me with one more

Solve: The sum of 7 times a number and 3 is 24.

A.7/3


B.3


C.3/7


D.1/3



Answer 5

@mathstudent55

Answer 6

Sure,

Answer 7

Like with the previous problem, the first step is to choose a variable to represent the unknown quantity.
Let x = the unknown number.

Answer 8

Now you read the sentence and translate the words into an equation.

Answer 9

a number = x
7 times a number = 7x
the sum of 7 times a number and 3 = 7x + 3

Answer 10

The sum of 7 times a number and 3 is 24.
7x + 3 = 24
Solve 7x + 3 = 24 for x

Answer 11

@mathstudent55 3?

Answer 12

Correct.

Answer 13

@mathstudent55 one more thing please?

2/3 · 3/2 = 1 is an example of which property?


Multiplicative Inverse 


Reflexive 


Inverse Operation 


Identity of Multiplication 

Answer 14

Reciprocals are also called multiplicative invereses. It's two numbers whose product is 1.

Answer 15

ok so its A. @mathstudent55

Answer 16

correct