Question

If x = 1, y = 2 and z = 5, find the value of 2x² − 3y² + z²

Answer 1

\[2 x^2 - 3 y^2 + z^2\]

Substituting x = 1, y = 2 and z = 5 in the given expression:
\[2 \times (1 )^2 - 3 \times (2 )^2 + 5^2 = 2 \times (1 \times 1) - 3 \times (2 \times 2) + (5 \times 5) = 2 - 12 + 25\]
\[ = 15\]