Question

2x - 40 = 2y
2y = 64 - 6x

Using the two equations above, solve for y.

Answer 1

so to find a variable, i was taught to substitute 0 for the other.

Answer 2

HI!!

Answer 3

if you divide the second equation all the way across by 2, you get \[y=32-3x\]

Answer 4

try dividing the first one by 2 and see what you get

Answer 5

then set the two expressions for \(y\) equal, solve for \(x\)

Answer 6

y=x-20

Answer 7

right so now solve \[32-3x=x-20\] for \(x\) in three steps

Answer 8

a) add \(3x\) to both sides
b) add \(20\) to both sides
c) divide both sides by \(4\)

Answer 9

I think this way is easier to visualize.

Rewrite using algebra so the x and y terms line up...

ax + by = c1
dx - ey = c2

in this form elimination of an x or y term is possible by addition or subtraction.

Answer 10

x=13

Answer 11

2x - 40 = 2y ------> 2x - 2y = 40
2y = 64 - 6x -----> 6x + 2y = 64

Now if I add the two equations.... The y term will equal 0

Answer 12

yes \(x=13\)

Answer 13

and since \(y=x-20\) that tells you \(y=13-20\)

Answer 14

2x - 40 = 2y ------> 2x - 2y = 40
2y = 64 - 6x -----> 6x + 2y = 64 add

8x +0y = 104
x = 104 / 8
as seen above x = 13

Answer 15

2x - 40 = 2y
2y = 64 - 6x --> x = 13 --> 2y = 64 - 78 --> y = 32 - 39 y = -7

Check by plugging answers into the other equation ....

2x - 40 = 2y x =13 y = -7

26 - 40 = -14 CHECKS