Question

Simplify the expression & find the value of the expression 3(a + 2b) + 4(-a -3b) + 3b -7a if a = 1 and b= -1.

Answer 1

Given :-

$\: \: \: \: \: \bull \tt \: Expression : \: 3(a + 2b) + 4(-a -3b) + 3b -7a$

To Find :-

$\: \: \: \: \: \: \: \: \bull\tt \: Value \: of \: expression \: if \: a = 1 \: and \: b = - 1$

Solution :-

Given expression is

$\tt \: 3(a + 2b) + 4(-a -3b) + 3b -7a$

Step :- 1.

We first simplifying the expression by open the parenthesis, so, we get

$\: = \: \tt \: 3a + 6b - 4a - 12b + 3b - 7a$

Step :- 2

Now, we have to collect up the like terms, we get

$\: = \: \tt \: (3a - 4a - 7a) + (6b - 12b + 3b)$

Step :- 3

Now, apply the Mathematical operations for evaluation,

$= \: \tt \: - 8a - 3b$

Step :- 4

Now, Substitute the value of a = 1 and b = - 1, we get

$= \: \tt \: - \: 8(1) \: - 3( - 1)$

$\: = \: \tt \: - \: 8 \: + \: 3$

$\: = \: \tt \: - \: 5$

Additional Information :-

An algebraic expression is a mathematical phrase that contains numbers and/or variables. Though it cannot be solved because it does not contain an equals sign (=), it can be simplified.

To evaluate an algebraic expression means to find the value of the expression when the variable is replaced by a given number.

To evaluate an expression, we substitute the given number for the variable in the expression and then simplify the expression using the order of operations.