2/5 - 7 * (-3)
2/5 - 7 * (-3) = 2/5 - (-21)
= 2/5 + 21
= 2/5 + 21/1 (converting 21 to a fraction)
= (2 * 1 + 21 * 5) / (5 * 1)
= (2 + 105) / 5
= 107/5
To evaluate the expression 2/5 - 7 * (-3), follow the order of operations (also known as PEMDAS). PEMDAS stands for:
P: Parentheses (simplify expressions inside parentheses first)
E: Exponents (perform exponentiation if there are any)
MD: Multiplication and Division (perform multiplication or division from left to right)
AS: Addition and Subtraction (perform addition or subtraction from left to right)
Let's break down the expression step by step:
1. Multiply: 7 * (-3)
To multiply a positive number by a negative number, multiply the numbers together and then change the sign of the result.
7 * (-3) = -21
2. Divide: 2/5
Divide the numerator (2) by the denominator (5).
2/5 = 0.4
3. Subtract: 0.4 - (-21)
To subtract a negative number, change the subtraction to addition and change the sign of the number being subtracted.
0.4 - (-21) = 0.4 + 21 = 21.4
Therefore, 2/5 - 7 * (-3) equals 21.4.