Question

How many solutions exist for the system y = 2x + 5 and y = -0.2x - 4?
A. no solution
B. one solution
C. infinitely many solutions

Answer 1

if we scale the 2nd by -4 we get 2x + 16

Answer 2

same x parts different constants; no solutions

Answer 3

opps, read .5 instead of .2

Answer 4

same concept tho :)

Answer 5

y = 2x + 5
-y = 0.2x + 4
-------------
0 = 2.2x + 9

x = -9/2.2

Answer 6

if that x produces the same ys were good

Answer 7

http://www.wolframalpha.com/input/?i=y+%3D+2x+%2B+5+and+y+%3D+-0.2x+-+4

says were good with one solution

Answer 8

Change -0.2 to -(2/10) and solve the following for x and y:\[\left\{y=2 x+5,y=-\frac{x}{5}-4\right\} \]\[\left\{x=-\frac{45}{11},y=-\frac{35}{11}\right\} \]