3a2-ab3+5 for a=5 and b=2

Question

the 2 by the a is meant to be a to the power of 2 or squared and the 3 by the b is meant to be b to the power of 3 or b cubed

Answer 1

for every "a", replace it with 5. and for every "b" replace it with 2. then you get:

3(5)^2 - 5(2)^3+5

order of operations (Parenthesis, Exponents, Multiply or divide (right to left) , Add or Subtract (right to left) says do the powers first

3(25) - 5(8) +5

then multiply

75 - 40 + 5

then add and subtract

75 - 40 = 35 + 5 = 40

 

 

Answer 2

The concept here is to know your order of operations and where to plug in what number. In this case, for every a in the equation, you replace it with a 5 and every b with a 2. Once that is done your equation will look like this:

3*(5)^2 - 5*(2)^3 + 5

Order of operations tells us that if there are no parenthesis, then we start with the exponents. Applying this leaves us with:

3*25 - 5*8 + 5

Next, it tells us to do all multiplication and division in order from left to right. This leaves us with :

75 - 40 + 5 

Finally, we do all addition and subtraction form left to right. This leads us to the final answer of:

40

Answer 3

 3a2-ab3+5 for a=5 and b=2

Substitute 5 for every "a" you see and 2 for every "b" you see

3(5)^2 - (5)(2)^3 + 5 = 3(5 * 5) - 5(2 * 2 * 2) + 5

Use your order of operations - PEMDAS

3(25) - 5(4 * 2) + 5 = 75 - 5(8) + 5 = 75 - 40 + 5 35 + 5 = 40

Answer 4

3a^2-ab^3+5 for a=5 b=2

so substitute

3(5^2)-(5*(2^3))+5

PEMDAS 

3(25)-(5*8)+5

solve

75-40+5=40   Ans.=40

Answer 5

Kenton,

So then you have 3(5)^2 - (5)(2)^3 +5

which reduces to

3(25) - 5(8) + 5

and gives

75-40+5 =

you can do the rest i'm sure

Hope this helps!

Art