If x = -2 and y = -3, what is the value of the expression 2x^2 - 5y? — Armed Services Vocational Aptitude Battery (ASVAB)

If $x = -2$ and $y = -3$ , what is the value of the expression $2x^2 - 5y$ ?

A
-7
B
7
23Cevap
D
31

Cevap

The expression is evaluated by first substituting the values and applying the exponent to the base, giving

(-2)^2 = 4

. Then, perform the multiplication to get

2(4) = 8

and

5(-3) = -15

. Finally, subtracting negative 15 from 8 is the same as adding 15, resulting in

8 + 15 = 23

Adım Adım Çözüm

Substitute the given values for

x

and

y

into the expression.

2(-2)^2 - 5(-3)

To evaluate the expression, each variable must be replaced with its corresponding numerical value.

Evaluate the exponent.

2(4) - 5(-3)

According to the order of operations (PEMDAS), exponents must be resolved before multiplication. The square of any non-zero real number is positive, so

(-2)^2 = 4

Perform the multiplication operations.

8 - (-15)

Multiply

2

4

to get

8

, and

5

-3

to get

-15

Perform the subtraction.

8 + 15 = 23

Subtracting a negative number is mathematically identical to adding its positive counterpart.

Anahtar Kavram

Evaluating expressions using substitution and the order of operations.

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