Let the angle=x

the complement=y

Therefore, x+y=90

We also know that 4y+5=x

now, it’s a simple matter of substition…from the second equation, we know what x is equal to, so lets substitute that into the first equation and solve for y. This gives us

4y+5+y=90

Now we need to group like terms, giving us

5y+5=90

Lets move the 5 to the other side of the equation. This will give us

5y+5-5=90-5 which becomes 5y=85

Now, lets isolate y

5y/5=85/5 which becomes y=17

Now that we know what y equals, lets solve for x.

We have the equation x+y=90

By rearranging the equation we get x=90-y

If we input our value for y we get x=90-17 which equals 73

So here, x = 4(90 – x) + 5

that’s x = 360 – 4x + 5

x = 365 – 4x

add 4x to both sides to get 5x = 365; divide by 5 and you get the 73.