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# use all three methods graphing,substitution,linear combination to solve 7x-3y=4 and -14x+6y=-8

after state how many solutions there are and give a reason
thanks

### 1 Answer by Expert Tutors

Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
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Hi Angelica;
7x-3y=4 and -14x+6y=-8

LINEAR COMBINATION
This equations are linear combinations.  Both equations have variables x and y with coefficients A and B.
Furthermore, the first equation is in standard format...
Ax+By=C, neither A nor B equal zero and A is greater than zero.
7x-3y=4
However, the second equation is NOT in standard format in that A is less than zero...
-14x+6y=-8
Let's fix that by multiplying both sides by -1...
-1(-14x+6y)=(-8)(-1)
14x-6y=8

SUBSTITUTION
7x-3y=4 and 14x-6y=8
Let's take the first equation...
7x-3y=4
Let's multiply both sides by 2...
(2)(7x-3y)=(4)(2)
14x-6y=8
It is identical to the second equation.

ZERO SOLUTIONS ARE POSSIBLE BECAUSE BOTH EQUATIONS ARE IDENTICAL.