Question

Evaluate the algebraic expression $a{x}^2+b{y}^2-c{z}^2$,

for $x=1$, $y=-1$, $z=2$, $a=-2$, $b=1$ & $c=-2$

• A. 5
• B. -9
• C. 7
• D. 11

Answer 1

The correct option is C 7

Given expression is $a{x}^2+b{y}^2-c{z}^2$,

Substituting the value of
$x=1$, $y=-1$, $z=2$, $a=-2$, $b=1$ & $c=-2$
in the above expression, we get

$=(-2)(1{)}^2+1(-1{)}^2-(-2)(2{)}^2$
$=-2+1+8$
$=7$

$\therefore$ The value of $a{x}^2+b{y}^2-c{z}^2$ when $x=1$, $y=-1$, $z=2$, $a=-2$, $b=1$ & $c=-2$ is 7.