Answer:
third one
Step-by-step explanation:
-14.4 - 8.1 = - 22.5
The outside temperature at noon is - 22.5 degrees
1/2x+20=1/3x+30
Subtract 20 on both sides
1/2x=1/3x+10
Subtract 1/3x on both sides
1/6x=10
Multiply by 6 on both sides
X=60
Let

be the amount of time it takes to perform an arm routine and

be the amount of time it takes to perform an abdominal routine. We see:


Subtracting the second equation from the first gives

. Substituting gives

, so

and

.
Thus, an arm routine takes ten minutes and an abdominal routine takes thirty minutes.
First you need to know the definition of a complementary angle. That means that two angles add up to 90 degrees, or a right angle.
To find an angle complementary to a 78 degree angle, you need to subtract 78 from 90.
90 - 78 = 12