Question

Show that (5x + 7y ) ^2 - 140 xy = ( 5x - 7 y) ^3​

Answer 1

Answer:

5x+7y−140xy=3x−14

Subtract 3x from both sides.

5x+7y−140xy−3x=−14

Combine 5x and −3x to get 2x.

2x+7y−140xy=−14

Subtract 7y from both sides.

2x−140xy=−14−7y

Combine all terms containing x.

(2−140y)x=−14−7y

The equation is in standard form.

(2−140y)x=−7y−14

Divide both sides by −140y+2.

2−140y(2−140y)x=2−140y−7y−14

Dividing by −140y+2 undoes the multiplication by −140y+2.

x=2−140y−7y−14

Divide −14−7y by −140y+2.

x=−2(1−70y)7(y+2)