please solve both ways and show steps. thank you
how do you solve the linear equation 4x - y = 5 and 4x + 4y = -4 using substituation AND elimination
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using substitution :
solve for one of the unknowns in one of the equations and substitute into the other equation.
y=4x-5 solving for y in the 1st equation
using this in the 2nd equation
substitute back into either equation
x=4/5 and y = -(9,5)
multiply the 2nd equation by -1
-y-4y=5+4 the 4x and the -4x on the left side cancel
now calculate x, either sub into the either equation or can multiply the 1st equation by 4 and add again
16x+4x=20-4 the -4y and the +4y cancel
same value for x and y as we had before.
Can substitute the answer into the original equation and check to see that we didn't make any mistakes.
Rearrange one of the equations:
Substitute into the other equation:
Substitute into one of the original equations to solve for y:
Subtract to eliminate one of the variables: