Question

If 3x – 4y = 10 and xy = - 1, find the value of 9x2 + 16y?
help please.​

Answer 1

Answer:

Given 3x-4y=10

And xy=(-1)

Now (3x-4y)²=10²=100

or (3x)²+(4y)²-2(3x)(4y)=100

or 9x²+16y²-24xy=100

or 9x²+16y²-24(-1)=100

or 9x²+16y²+24=100

or 9x²+16y²=100-24=76

If my answer satisfies you then give me thanks.

Answer 2

Answer:

76

Step-by-step explanation:

3x - 4y = 10

Squaring both sides,

We get

$(3x - 4y)^{2} = 10^{2}$

$(3x)^{2} + (4y)^{2} -2(3x)(4y) =100\\\\9x^{2} + 16y^{2} -24xy = 100$

Putting value of xy = (-1) from question.

We get,

$9x^{2} + 16y^{2} -24(-1) = 100\\\\9x^{2} + 16y^{2} + 24 = 100\\\\9x^{2} + 16y^{2} = 100 - 24\\9x^{2} + 16y^{2} = 76$

HOPE IT HELPS YOU