Answer:
Step-by-step explanation:
4.5x=90
x=20 history
28 chemistry
42 math
They add to 90.
History test=x
Chemistry test=1.4x
Math test=(1.5)(1.4)=2.1x
They add to 90
Answer:

Step-by-step explanation:
A road is perpendicular to a highway leading to a farmhouse d miles away.
An automobile passes through the point of intersection with a constant speed
= r mph
Let x be the distance of automobile from the point of intersection and distance between the automobile and farmhouse is 'h' miles.
Then by Pythagoras theorem,
h² = d² + x²
By taking derivative on both the sides of the equation,




When automobile is 30 miles past the intersection,
For x = 30

Since 
Therefore,


Answer:
Thank you lol. I am so bored right now.
Step-by-step explanation:
Answer:
x=-5
Step-by-step explanation:

The answer is 58 I think 166-8= 158