Posted by Julie Jam on Wednesday, December 8, 2010 at 1:11pm.
A. 3x + y = 8
B. x- 1/2y =2
C. x + 2y = 9
2y = -x + 13
I am not grasping the substitution method! Please help me.
- algebra - Reiny, Wednesday, December 8, 2010 at 1:40pm
Pick the equation for which it is easier to "isolate" one of the variables.
A) from the second: x = 6+y
plug that into the first
3x + y = 8
3(6+y) + y = 8
18 + 3y + y = 8
4y = -10
y = -5/2
now put that back into the easier of the two
x = 6+y
x = 6 - 5/2 = 7/2
b) really easy, y is already isolated
c) notice we have 2y isolated , but 2y shows up in the first, so again, real easy
x + 2y = 9
x + (-x + 13) = 9
13 = 9 ?????
ahhh, this last pair of equation has no solution, (we got a silly statement)
Answer This Question
More Related Questions
- algebra - use the Substitution Method. Please give it a try. y = 3x + 4 5x + 3y...
- Algebra 1 - bobpursey, In this problem you helped me with earlier: Solve using ...
- Algerbra 1 substitution method - im really confused about this question: 2x-3y=...
- Algebra II - How do you solve the linear equations x+y=5 3x-y=3 by use of the ...
- Algebra - Explain why the addition method might be preferred over the ...
- Math - 1. Explain the advantages and disadvantages of both the substitution ...
- Algebra - Solving system of linear equations by using the apropiate method name ...
- substitution method - Solve by substitution method please help me solve this. I ...
- Linear Equations - Can you please help solve this equation using the ...
- Algebra - Systems of equations can be solved by graphing or by using ...