Two two-digit numbers, 'AB' and 'BA', sum to produce a three-digit number in which the second digit
is equal to A. The addition is represented below. (Note
that the variables are used to represent individual digits;
no multiplication is taking place).
AB + BA= 1A2
What is B?

9514 1404 393

  9

Step-by-step explanation:

The value of the sum is ...

  (10A +B) +(10B +A) = 102 +10A

  11A +11B = 102 +10A

  A +11B = 102 . . . . . . . subtract 10A

Dividing by 11, we have ...

  A/11 +B = 9 3/11

This tells us A=3, B=9.

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Check

39 + 93 = 132

a) 7x=7

step-by-step explanation:

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752