How do i work this math problem: y=1/2x-4;(2, ),( ,-7)

Question

I am new to Algebra and do not know how to work this math problem:  y=1/2x-4;(2, ),( ,-7)

Thank you for your help!

Answer 1

What's essentially happening is that each case we're given an variable, and we need to find the other.

(2, ) means that the x-variable is at 2, so we need to solve for y:

y = ½ * 2 - 4

y = 1 - 4

y = -3

So we have (2, -3)

 

In the other case, ( , -7), we have a y value and thus need to solve for x:

-7 = ½x - 4

add 4 to both sides:

-7 + 4 = ½x

-3 = ½x

Multiply both sides by 2:

-3 * 2 = x

-6 = x

So we have (-6, -7)