Answer:
84
Step-by-step explanation:
f(x) = 3x^2 + 2x – 1
Let x=5
f(5) = 3(5)^2+2(5) -1
= 3*25 +10-1
= 75+10 -1
= 85 -1
D=228
when 2 numbers or variables are next to eachother it means you need to multiply. So in this case r=57 and t=4 and we mulitply. 57 x 4 = 228. So the answer is 228. Hope this helps and have a great day!
Answer:

Step-by-step explanation:
I suggest looking lessons on it online if you don't understand... It's hard to do your work especially if you don't understand it. Or if your online, go to past lessons or something.