Anonymous
Anonymous asked in Education & ReferenceHomework Help · 8 years ago

1. If y varies directly as x, find the constant of variation if y = 25 and x = 5.

a. 5

b. 125

c. -5

d. -125

2. Which of the following represents a direct variation?

a. y=10^x

b. y=10/x

c. y=10x^2

d. y= 10x

3. Write an appropriate direct variation equation if y=45 when x=5.

a. y=9x

b. y=225x

c. y=9/x

d. y=225/x

4. Which of the following is an exponential function?

a. y=5x

b. y=6^x

c. y=log5x

d, y=x^2

5. Write y=10^x as a logarithmic function.

a. log 10x=y

b. log 10=y

c. log 10y=x

d. log 10=x

6. Determine if the equation y=2(0.45)^x represents A. exponential growth

B. exponential decay

7. Write ^4√(x^3) in exponential form.

a. 3/x4

b. 4/x3

c. x -3/4

d. x^3

8. What is the solution of 3|r+5|≤6?

a. x ≥ -3 and x ≤ -7

b. no solution

c. x = ≥ -3 and x ≤ -7

d. x < -3 or x > -7

Relevance
• Erin
Lv 4
8 years ago

1) A

2) B

3) A

4) B

5) A

6) A

7) I don’t know

8) A except for I think it’s x is greater than or equal to -7 not less than or equal to

1-2) When two variables are related in such a way that the ratio of their values are the same the two variables are direct variation.

3) If y varies directly as x than y=kx where k is a constant. Substitue the values of x and y to sovle for k: y=k*k so 45=k*5 so k=9 so the equation is y=9x.

4) exponential function: a mathematical expression with the formula e^x, in which e is the base of natural logarithms.

6) the exponent is positive

8) order of operations, remember to use two cases and flip the sign when dividing by a negitive