Subtraction method

Question

Solving 3x+4y=-10, x= 10-8y

Answer 1

Would be better solved by substitution as we have x=10-8y

 

3x + 4y = -10

 x  + 8y = 10 <--- rewrites second equation

 

Multiplies bottom equation by 3

 

3x + 4y = -10

3x + 24y = 30

 

 

Subtracts:

 

-20y = -40

y = -40/-20 = 2

 

x = 10 - 8(2) = 10 - 16 = -6

 

(x = -6 , y = 2)