Question

Choose the inverse of y = x2 - 10x.

Answer 1

=Y2-10Y

We move all terms to the left:

-(Y2-10Y)=0

We add all the numbers together, and all the variables

-(+Y^2-10Y)=0

We get rid of parentheses

-Y^2+10Y=0

We add all the numbers together, and all the variables

-1Y^2+10Y=0

a = -1; b = 10; c = 0;

Δ = b2-4ac

Δ = 102-4·(-1)·0

Δ = 100

The delta value is higher than zero, so the equation has two solutions

We use following formulas to calculate our solutions:

Y1=−b−Δ√2aY2=−b+Δ√2a

Δ‾‾√=100‾‾‾‾√=10

Y1=−b−Δ√2a=−(10)−102∗−1=−20−2=+10

Y2=−b+Δ√2a=−(10)+102∗−1=0−2=0