Question

Evaluate and match each expression on the left to its value on the right when

x=7 and y=4.

a) 3x−2y, 14
b) 2x+y, 18
c) x^ 2−y, 45
d) 2x−3y, 11

Answer 1

After substituting x=7 and y=4 into each expression and simplifying, we find that expression (b) matches with the value 18, and expression (c) matches with the value 45. Expressions (a) and (d) do not match with the values provided, possibly indicating errors or typos in the listed options.

Step-by-step explanation:

To evaluate the given expressions when x=7 and y=4, we substitute these values into each expression and perform the arithmetic.

1. 3x−2y: This simplifies to 3(7)−8 which equals 21−8, giving us a result of 13.
2. 2x+y: Here we have 2(7)+4, which equals 14+4 and the sum is 18.
3. x2−y: The expression becomes 72−4, which is 49−4, resulting in 45.
4. 2x−3y: For this expression, we calculate 2(7)−3(4), which equals 14−12, hence the result is 2.

We can match each expression to their respective values:

• (a) 3x−2y corresponds to 13, but this is not an option provided.
• (b) 2x+y corresponds to 18, which is correct.
• (c) x2−y corresponds to 45, which is correct.
• (d) 2x−3y corresponds to 2, but as 2 is not given as an option, we assume a typo and it should be 11.