Question

what should be subtracted from 2x^2 -5y^2 +7z^2 to get x^2 - y^2+ z^2
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Answer 1

Step-by-step explanation:

let the polynomial to be subtracted be X

let the first polynomial beA, second be B

A- X=B

X=A-B

2x²-5y²+7z² ----A

x² -y² +z² ----B

- + -

_________

x² -4y²+6z² ----X

_________

Answer 2

Let N be subtracted from 2x² - 5y² + 7z² to get x² - y² + z²

$\longrightarrow$ (2x² - 5y² + 7z²) - N = x² - y² + z²

$\longrightarrow$ (2x² - 5y² + 7z²) - N - (2x² - 5y² + 7z²) = (x² - y² + z²) - (2x² - 5y² + 7z²)

$\longrightarrow$ - N = (x² - y² + z²) - (2x² - 5y² + 7z²)

$\longrightarrow$ - N = x² - y² + z² - 2x² + 5y² - 7z²

$\longrightarrow$ - N = x² - 2x² - y² + 5y² + z² - 7z²

$\longrightarrow$ - N = - x² + 4y² - 6z²

$\longrightarrow$  N = -(- x² + 4y² - 6z²)

$\longrightarrow$  N = x² - 4y² + 6z²