Question

the value of the expression $6c^2 - 5d + 8$ when $c = 5$ and $d = 4$ is ______

Explanation:

Step1: Substitute c = 5 and d = 4 into the expression

First, calculate \( c^2 \) when \( c = 5 \), so \( 5^2 = 25 \). Then the term \( 6c^2 \) becomes \( 6\times25 \). The term \( -5d \) becomes \( -5\times4 \) when \( d = 4 \). The expression now is \( 6\times25 - 5\times4 + 8 \).

Step2: Calculate each term

Calculate \( 6\times25 = 150 \), \( -5\times4 = -20 \). Now the expression is \( 150 - 20 + 8 \).

Step3: Perform the arithmetic operations

First, \( 150 - 20 = 130 \), then \( 130 + 8 = 138 \).

Answer:

138