Answer:
Acute
Step-by-step explanation:
The solution to the expressions given are;
9 -9t/ 12 - 5t
a. 20/ 169
b. -170/ 169
c. 386/ 169
d. -10/ 169
<h3>How to solve the expressions</h3>
Given:

We can see that both variables in the numerator and denominator have no common factor, thus cannot be factorized further
a. 
First, let's find the lowest common multiple
LCM = 169
= 
= 
= 20/ 169
b. 
The lowest common multiple is 119
= 
substract the numerator
= - 170/ 119
c. 
The lowest common multiple is 169
= 
= 386/ 169
d. 
The lowest common multiple is 169
= 
= - 10/ 169
Thus, we have the solutions to be 9 -9t/ 12 - 5t, 20/ 169, -170/ 169, 386/ 169, -10/ 169 respectively.
Learn more about LCM here:
brainly.com/question/12732917
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Step-by-step explanation:
Rate of drop of temperature = Change in temperature/Rate
=> (165 - 135)/15
=> 30/15
=> 2 ⁰F/min
Now, The time at which the temperature of will be 70⁰F = 70/Rate
=> 70/2
=> 35 min
Time for 110⁰ F
=> 110/2
=> 55 min
Proportional equations are the equations that have the graph which pass through (0,0).
y = -9x is proportional.
y=x is proportional
y=1/2x is proportional
That's it. Only these three equations have (0,0) intercept.