Question

Evaluate the expression when y=-7.
y? +4y-1

Answer 1

On substituting
`y  = -7 , y^(2) + 4y -1  = 20`

Explanation:

The given expression =
`y^(2) + 4y -1`

Substitute y = -7 in the above quadratic equation:

`(-7)^(2) + 4(-7) -1` = (-7)(-7) + (-28) -1

= 49 -28 -1 = 49- 29 = 20

So, on substituting
`y  = -7, y^(2) + 4y -1  = 20`