Quiz 7.1-7.4

Which of the following represents an exponential function?

• $y=4x-8$

• $y=4^x+7$

• $y=x^2+2x+1$

• $y=3x^3$

Which of the following equations could describe the graph shown?

• 
  

  $y=x^2-6$
  

• $y=2x-1$

• $y=\left(\frac{3}{4}\right)^x$

• $y=5^x$

If $150 is invested in a savings account that earns 6% interest per year, which of the following is closest to the amount in the account at the end of 10 years?

• 16493

• 269

• 81

• 450

Given that a population can be modelled by the equation  $P=170\left(1.085\right)^t$  , which of the following is true?

• The initial population was 170 and the population is growing at a rate of 8.5%

• The initial population was 134 and the population is growing at a rate of 85%

• The initial population was 170 and the population is growing at a rate of 85%

• The initial population was 134 and the population is growing at a rate of 8.5%

If a radioactive substance is quickly decaying at a rate of 19% per hour, approximately how much of a 500 kg sample remains after one day?

• 125.2 kg

• 2.4 kg

• 467.6 kg

• 3.2 kg

Find the y-intercept.

 $y=2\cdot\left(\frac{1}{2}\right)^x$  

• 2

• 1

• 0

• 0.5

• 4

Which of the following functions represent exponential growth? Select all that apply.

• 
  

  $y=0.5^x$
  

• $y=\left(\frac{5}{4}\right)^x$

• $y=7^x$

• $y=10\left(\frac{1}{3}\right)^x$

• $y=3^x-0.7$

Solve for x. Type your answer as a number without any variables.
 $5^{\left(x+1\right)}=5^{\left(2x-6\right)}$  

Solve for x. Type your answer as a number without any variables.

 $4^{\left(2x-7\right)}=8^{\left(x-1\right)}$  

 $\frac{1}{27}^{\left(x+4\right)}=9^{\left(x-7\right)}$  

Which value of x is a solution to the equation?

•  $\frac{2}{5}$  

•  $4$  

•  $1$  

•  $\frac{5}{2}$  

• none of these