Question

Evaluate 10x2y–2 for x = –1 and y = –2.

Answer 1

`10x^2y^(-2)`
Substitute the values of x = -1 and y = -2 to the expression:

`10\cdot(-1)^2\cdoy(-2)^(-2)=10\cdot1\cdot(1)/((-2)^2)=10\cdot(1)/(4)=(10)/(4)=2.5`
Used:
`a^(-n)=(1)/(a^n)`

Answer 2

Substituting the values of x and y will give 38

Explanation:

The question seeks to test our understanding of Substitution

Given the expression

10x2y–2 for x = –1 and y = –2.

Substituting for the value of x and y into the expression

We are given x=-1

y=-2

Substituting and equating to zero we have

10(-1)2(-2)-2=0

Opening up The bracket we have

(-10)(-4)-2=0

40-2=0

38=0

The emerging answer is 38