Question

Rosana used linear combination to solve the system of equations shown. She did so by multiplying the second equation by a certain number to eliminate the y-terms. What number did Rosana multiply the second equation by?
`\left \{ {{x - y = 16} \atop {0.5x + 0.2y = 25}} \right.`

Answer 1

She multiplied it by 5, because that would make the equation:

2.5 + y = 125

So when we add -y and y cancel out