Solving System of Equations ( linear and linear)

Question

 y=5x+3

 y=3x-4

Answer 1

5x+3 = 3x-4

2x+3=-4

2x = -7

x = -7/2

check:

5(-7/2)+3 = -35/2 + 3 = -35/2 + 6/2 = -29/2

3(-7/2)-4 = -21/2 - 4 = -21/2 - 8/2 = -29/2

x = -7/2, y = -29/2

Answer 2

Elimination method 

y=5x+3

 y=3x-4

Subtract the bottom equation from the top.

0 = 2x +7

solve for x

x = - 3.5

solve for y using either original equation

y = 5(-3.5) +3

y = -14.5

Substitution method

y=5x+3

 y=3x-4

Substitute 5x + 3 for y in the second equation

5x +3 = 3x - 4

solve for x

2x = -7

x = -3.5 find y as in the elimination method.