I just need help so can someone help me with the answer and walk me through the work

8. 4x²+3y = 4(4)²+3(5) = 4(16)+15 = 64+15 = 79
basically you have to substitute the variable for the given value. (ex. x is replaced by 4 and y is replaced by 5 and z is replaced by 3) FOR BOTH PROBLEMS!
9. (y+z)/x = (5+3)/4 = 8/4 = 2