Question

PLS HELP WILL MARK BRAINLIEST

Answer 1

The image will explain everything

Answer 2

$\sf \longmapsto7x^2+6xy−y^2$

• Put the values

$\sf \longmapsto7( {2}^{2} )+(6)(2)(−1)−(−1) {}^{2}$

• Solving Further

$\sf \longmapsto(7)(4)+(6)(2)(−1)−(−1) {}^{2}$

$\sf \longmapsto28+(6)(2)(−1)−(−1) {}^{2}$

$\sf \longmapsto28+(12)(−1)−(−1) {}^{2}$

$\sf \longmapsto28+−12−(−1) {}^{2}$

$\sf \longmapsto16−(−1)²$

$\sf \longmapsto16−1$

$\sf \longmapsto15$