Question

From 7x2+5xy−3y2 subtract the sum of 2x2+3xy−5y2 and x2−7xy−4y2.

Answer 1

Answer:   $4x^{2} +9xy+6y^{2}$

Step-by-step explanation:

First equation $=$ $2 x^{2} +3xy-5y^{2}$

Second equation $=$ $x^{2} -7xy-4y^{2}$

Third equation $=$ $7x^{2} +5xy-3y^{2}$$3x^{2} -4xy-9y^{2}$

Sum of the following of two valuable equation first and second

$(2x^{2} +3xy-5y^{2} ) + (x^{2} -7xy-4y^{2} )$

$(2+1) x^{2} +(3-7)xy+(-5-4)y^{2}$

$3x^{2} -4xy-9y^{2}$

Subtract third equation from the sum of two valuable expression

$(7x^{2} +5xy-3y^{2} ) - (3x^{2} -4xy-9y^{2} )$

$(7-3)x^{2} +(5-(-4))xy +(-3-(-9))y^{2}$

$4x^{2} +9xy+6y^{2}$