Question

WILL GIVE MEDAL TO BEST RESPONSE

Use substitution to determine which of the following points is a solution to the standard form equation below.

3x-5y=8

a. (1,1)
b. (1,-1)
c. (-1,1)
d. (-1,-1)

Answer 1

multiply so you can subtract to eliminate a variable

(3x - 5y = 8) x4 12x - 20y = 32
(4x - 7y = 10) x3 12x - 21y = 30


subtract the second from the first...

12x - 20y = 32
- (12x - 21y = 30)
y = 2

substitue the y back into the original problems


3x - 5 (2) = 8
3x - 10 = 8
3x =18
x = 6



y = 2 and x = 6 if put them both back into the problem then you should get the answer on the other side....

Answer 2

so it is just this equation?

3x-5y=8


Well just take each of the potential points ...and substitute them in for 'x' and for 'y'

so for example....choice A says (1 , 1) (x , y) so replace ever 'x' with 1 and 'y' with 1

3x - 5y = 8

3(1) - 5(1) = 8

3 - 5 = 8

-2 = 8

This is not true...so it is not the right choice....just follow that for the other choices until you find the answer