Question

One way of solving systems of linear equations is by adding a multiple of one equation to the other. The multiplier for the first equation is chosen so that one of the two variables will cancel out in the sum. What should you multiply the equation y=0 y=0 by so that when added to x+y=40 x+y=40 the variable y yy will cancel out?

Answer 1

Multiply y = 0 by -1

Explanation:

Given

y = 0 (1)

x + y = 40 (2)

What should you multiply the equation y=0 by so that when added to x + y = 40, the variable y will cancel out ?

Multiply (1) by -1

y = 0 × -1

-y = 0 (1b)

Add (1b) and (2)

-y = 0

x + y = 40

(0 + x) + (-y + y) = 0 + 40

x + (0) = 40

x = 40

You should multiply the equation y = 0 by -1 so that when added to x + y = 40 the variable y will cancel out