Expert: Richard J. Raridon - 10/3/2008

Question
I have four problems that I cant figure out and need help with.

1. solve the system
y=2x=3
y=4x=7
using the substitute method show all of your work and write your answer in a sentence.

2. solve the system
5x-7y=-46
-3x-4y=3
using the addition method show all of your work and write your anwser in a sentence

3. solve the system
4x-6y=2
12x-18y=10
using the addition method show all your work and wite your answer in a sentence.

4. solve the system
3x=y=-3
5x=4y=2
by graphing show all of your work and write your answer in a sentence.

Answer
1. I presume you mean y=2x+3 and y=4x+7
so 2x+3 = 4x+7 giving you x = -2 and y = -1
2. multiply the 1st eq. by 3 to get 15x-21y = -138
and multiply the 2nd eq. by 5 to get -15x-20y = 15
add those to get -41y = -123 so y = 3 and x = -5
3. lines are parallel, no solution
4. Again, I assume you mean 3x+y = -3 and 5x-4y = 2
I can't graph for you but it only takes two points to draw a straight line.  They cross at (-2,-3)