SOLUTION: Simultaneous equation help! The answer at the back is (2,1) to this question: 2x-3y=7 3x+y=7 ??

Algebra.Com
Question 1001166: Simultaneous equation help! The answer at the back is (2,1) to this question:
2x-3y=7
3x+y=7
??

Answer by Cromlix(4381)   (Show Source): You can put this solution on YOUR website!
Hi there,
Think you have put a negative instead
of a positive in line 1
2x - 3y = 7 should read 2x + 3y = 7
2x+3y=7........(1)
3x+y=7.........(2)
Multiply (1) by 3
Multiply (2) by 2
6x + 9y = 21......(1)
6x + 2y = 14......(2)
Subtract (2) from (1)
....7y = 7
.....y = 1
Substitute y = 1 in (2)
3x+y=7.........(2)
3x + 1 = 7
3x = 7 - 1
3x = 6
x = 2
Answer (2,1)
Hope thi shelps :-)

RELATED QUESTIONS

Simultaneous equation help! The answer at the back to this question is (3,-1). The... (answered by Cromlix)
Please help me solve this substitution problem. 3(x-y)=15 2x+y=7 The question I have... (answered by MathTherapy)
what is the solution set of this simultaneous equation 2x + 3y = 10 and 3x - 2y = 2... (answered by Boreal)
what is the soultion to this simultaneous equation using substion or addtion method?... (answered by stanbon)
(5,1) is a solution to the equation 2x-3y=7.what does it mean? (question 1)... (answered by stanbon)
solve the simultaneous equation: 4x-3y=7... (answered by Fombitz)
Solve the simultaneous equation 2x-3y=17 and... (answered by ikleyn,Boreal)
This question is from a study handout, not the book per se. This is finding the inverse... (answered by Earlsdon)
Solve the following pairs of simultaneous equations using an inverse matrix. Show working (answered by ikleyn)