Question

Evaluate the algebraic expression “2a (a – 2b)” when a = 2 and b = -5.

Answer 1

Answer: 48

Concept:

Here, we need to understand the idea of evaluation.

When encountering questions that gave you an expression with variables, then stated: "If x = a, y = b, z = c" (a, b, c are all constants), this means you should substitute the value given for each variable back to the expression.

Solve:

Given information

a = 2

b = -5

Given expression

2a (a - 2b)

Substitute values into the expression

=2 (2) ((2) - 2 (-5))

Simplify by multiplication

=4 (2 - (-10))

=4 (2 + 10)

Simplify by addition

=4 (12)

Simplify by multiplication

=
`\boxed{48}`

Hope this helps!! :)

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