Algebra I PRAPT61911378710-1 Blackmore - NISO Algebra 1 3rd Nine Weeks
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Solving Systems of Linear Equations - Item 31353
Question 3 of 7
Derrick adds equations A and B to solve this system of equations. What makes this
approach a valid method in general for solving a system of equations?
Refere
Equation A: 5x + 4y = 24
Equation B: 3x - 4y - 16
&x40
CHECK
As long as addition is used on both sides or subtraction is
used on both sides, a true equation will remain true.
Language
Adding a quantity like 5z + 4y to one side of an equation
and another quantity like 24 to the other side maintains
the equality if the two quantities are equal.
ENGLISH
Because the y-terms cancel:
The method will give the correct solution, I = 5 and
y=-1
(5z + 4y)+(3x - 4y)=5z + 3x + 4y - 4y = 8z
5(5)+(-4)= 24