Question

Need help setting up two equations properly.
However, I can solve the rest... just need help setting them up! :)

Answer 1

1. Five less than twice the square a number, the result is 7 more than three times a number
2. A motorcycle can travel 705 miles on 19 gallons of gas. How many gallons of gas are needed for traveling 1253 miles?

Answer 2

1. ) 5 - (2x)^2 = 7 + 3x

2.) I don't know :D

Answer 3

Lol, thanks for your help anyhow @yamyam70 :)

Answer 4

:)

Answer 5

1. 2(x^2) - 5 = 3x + 7

2. I know a proportion...
705/19 = 1253/x (705 miles to 19 gallons = 1253 miles to x gallons)
you can solve this by cross multiplying and then solve for x.

Answer 6

The best way to do 1. is to deal with each part of the sentence and build up the expression.

"1. Five less than twice the square a number, the result is 7 more than three times a number"

Let x = a number
The "square of a number " is \(x^2\)
"twice the square of a number is" \(2x^2\)
"five less than twice the square of a number" is \(2x^2 - 5\)

"three times a number" is 3x
"7 more than three times a number" is 3x + 7

Now we equate both parts:
\(2x^2 - 5 = 3x + 7\)

Answer 7

@yamyam70
Be careful with "5 less than y."
It is y - 5, not 5 - y.

Answer 8

oh yeah, thanks again @mathstudent55 :)

Answer 9

mathstudent....on the second one, do you solve it with a proportion ?

Answer 10

@texaschic101
Yes, you did a great job, and your method of solving is good too.

Answer 11

thank you

Answer 12

wlcm