Question

1. If A = 4x² + y² - 6xy;

B = 3y² + 12x²+ 8xy;

C = 6x² + 8y²+ 6xy

Find


( i ) 2A + B
sol:​

Answer 1

Answer:

A=4x

2

+y

2

−6xy

B = {3y}^{2} + {12x}^{2} + 8xyB=3y

2

+12x

2

+8xy

C= {6x}^{2} + {8y}^{2} + 6xyC=6x

2

+8y

2

+6xy

Now,

A - B = {4x}^{2} + {y}^{2} - 6xy - {3y}^{2} - {12x}^{2} - 8xyA−B=4x

2

+y

2

−6xy−3y

2

−12x

2

−8xy

\: \: \: \: \: = { - 8x}^{2} - {2y}^{2} - 14xy=−8x

2

−2y

2

−14xy

Also,

(A - B) - C = ({ - 8x}^{2} - {2y}^{2} - 14xy) - {6x}^{2} + {8y}^{2} + 6xy(A−B)−C=(−8x

2

−2y

2

−14xy)−6x

2

+8y

2

+6xy

\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = { - 14x}^{2} - {10y}^{2} - 20xy=−14x

2

−10y

2

−20xy