Question

leveled practice in 1–2, fill in the boxes to complete the problems.

1. evaluate ( 3.6x + 4.5y ) when ( x = 3 ) and ( y = 7 ).

( 3.6 cdot square + 4.5 cdot square )
( = square + square )
( = square )

1. evaluate ( 5.5r - 8.35s ) when ( r = 12 ) and ( s = 4 ).

( 5.5 cdot square - 8.35 cdot square )
( = square - square )
( = square )

Explanation:

Problem 1: Evaluate \( 3.6x + 4.5y \) when \( x = 3 \) and \( y = 7 \)

Step1: Substitute \( x \) and \( y \) values

We substitute \( x = 3 \) and \( y = 7 \) into the expression \( 3.6x + 4.5y \), so we get \( 3.6 \cdot 3 + 4.5 \cdot 7 \).

Step2: Calculate each product

Calculate \( 3.6 \cdot 3 \): \( 3.6\times3 = 10.8 \)
Calculate \( 4.5 \cdot 7 \): \( 4.5\times7 = 31.5 \)
Now the expression becomes \( 10.8 + 31.5 \)

Step3: Add the two results

Add \( 10.8 \) and \( 31.5 \): \( 10.8 + 31.5 = 42.3 \)

Step1: Substitute \( r \) and \( s \) values

We substitute \( r = 12 \) and \( s = 4 \) into the expression \( 5.5r - 8.35s \), so we get \( 5.5 \cdot 12 - 8.35 \cdot 4 \).

Step2: Calculate each product

Calculate \( 5.5 \cdot 12 \): \( 5.5\times12 = 66 \)
Calculate \( 8.35 \cdot 4 \): \( 8.35\times4 = 33.4 \)
Now the expression becomes \( 66 - 33.4 \)

Step3: Subtract the two results

Subtract \( 33.4 \) from \( 66 \): \( 66 - 33.4 = 32.6 \)

Answer:

\( 3.6 \cdot \boldsymbol{3} + 4.5 \cdot \boldsymbol{7} \)
\( = \boldsymbol{10.8} + \boldsymbol{31.5} \)
\( = \boldsymbol{42.3} \)

Problem 2: Evaluate \( 5.5r - 8.35s \) when \( r = 12 \) and \( s = 4 \)