If a = 5 and b=2 then find the value of - 2ab and - 3a+b

Step-by-step explanation:

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 = 5

b = 2

Given expression

2ab

Substitute values into the expression

2 (5) (2)

Simplify by multiplication

=10 (2)

=

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Given information

a = 5

b = 2

Given expression

-3a + b

Substitute values into the expression

-3 (5) + (2)

SImplify by multiplication

=-15 + (2)

Simplify by addition

=

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