Anonymous
Anonymous asked in Science & MathematicsMathematics · 4 weeks ago

Math problem?

If a=5, b=3 and c=9

How is

5a + 3b - c = 25

I get 23 using the rules of bidmas as follows:

(5x5) + (3x3) - 9

25 + 9 - 9

34 - 9

Am I doing it wrong using bidmas to solve?

Any help to explain why I should subtract prior to addition, when it's that order, will be greatly appreciated.

Relevance
• sepia
Lv 7
3 weeks ago

5a + 3b - c

= 25 + 9 - 9 (if a = 5, b = 3 and c = 9)

= 25

• 4 weeks ago

5(5)+3(3)-9=25

25+9-9=25

25=25

Math seems to be working today.

• 4 weeks ago

Are you doing the last subtraction correctly?

34

-9

----

25

I don't see where you get 23

One other reminder about BIDMAS/BODMAS/PEMDAS or whatever mnemonic you are using.

Multiplication and Division have equal precedence so when you are doing those operations, go left to right.

Similarly, Addition and Subtraction have equal precedence, so when you do those, also go left to right.

• 4 weeks ago

sum of

9+(-9)=0

you are not completing the process.

• 4 weeks ago

34 - 9 = 25, not 23

• 4 weeks ago

5a + 3b - c = 25

5(5) + 3(3) - 9

25 + 9 - 9

= 25 prove.

• Bill
Lv 6
4 weeks ago

5X5=25,3X3= 9 so 5a +3B =25 +9=  34-9 =25

• 4 weeks ago

If a = 5, b = 3 and c = 9

5a + 3b - c = 25

How?

(5×5) + (3×3) - 9

= 25 + 9 - 9

= 34 - 9

= 25

• 4 weeks ago

Technically, when adding and subtracting, you do so in order as they appear from left to right. This means that your steps are correct, meaning that it should look like this:

5(5)+3(3)-9=25

25+9-9=25

34-9=25

25=25

left side=right side

;))

• 4 weeks ago

How are you getting 23 from 34 - 9?  34 - 9 = 25