Question

Work out the value of 3c - 4d when c = 5 and d = 1 over 2 ( 1 and a half )

Please help me out with this one , thanks! From my maths homework , could you please show working out as well please?

Answer 1

3(5) - 4(1/2) = 15 - 2 = 13

Answer 2

3c - 4d ; c = 5 ; d = 1/2

Remember this order of operation:
PEMDAS (Parenthesis, Exponent, Multiply, Divide, Add, Subtract)

3(5) - 4(1/2) Substitute the letters by its value
⇒15 - (4*1)/2
In multiplying fractions, numerator * numerator / denominator * denominator = in this case, 4/1 * 1/2 ; 4 and 1 are the numerators; 1 and 2 are the denominators.

⇒15 - 4/2 After multiplication, perform division
⇒15 - 2 no addition, so proceed to subtraction.
⇒13

3c - 4d = 13