Question

Evaluate the expression below for x = 4, y = –5, and z = 2.

3x^2 -4y+xz


A.12

B.36

C.52

D.76

Answer 1

76

Explanation:

Substitute the values into the expression

• x = 4
• y = –5
• z = 2.

3x^2 -4y+xz

3(4)^2 -4(-5)+(-5)(2)

Use BIDMAS, or another alternative.

B - Brackets.

We don't have any operations in brackets. We only have integers on their own.

I - Indices.

(4)^2 = 16

Substitute this into the expression

(3)(16) - 4(-5) + (-5)(2)

D - Division, M - Multiplication

Two brackets side by side means multiply.

(3)(16) = 3 * 16 = 48

4(-5) = 4 * -5 = -20

(4)(2) = 4 * 2 = 8

Substitute this into the expression.

48 - -20 + 8

A - Addition, S - Subtraction

Two minus signs become addition.

However, two different signs means minus.

48 - -20 + 8

48 + 20 + 8

68 + 8

76

Answer 2

D. 76

Explanation:

Put x = 4, y = -5 and z = 2 to the expression 3x² - 4y + xz and use PEMDAS:

3(4)² - 4(-5) + (4)(2)

= 3(16) + 20 + 8

= 48 + 20 + 8

= 76