Answer:
36
Explanation:
I don’t know if this half the problem or something because you only need to know what a equals but...
1. Substitute x for 4 since x=4... so the equation would then be (4)^2+10(4)-20
2. You simplify so 4 squared is 16 because when you square something you times it by it self so 4^2 is simply 16 because 4*4=16 then 10*4 is 40 so then you get 16+40-20
3. So you can simplify that again to 56-20 and then to 36
Sorry I’m really bad at explaining but I hope this helps