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Jared J. Algebra 12 months ago
If we do so we decrease the first number by 18. So, #10a+b-18=10b+a# # or, 10a-a+b-10b=18# # or, 9a-9b=18# # or, 9 (a-b)=18# # or, (a-b)=(18/9)# # or, (a-b)=2#...... (2) Solving equation (1) and (2) In equation (2). Substitute in equation (1). Re substitute in equation (1) The numbers are #4# and #6#
Logan H. It is basically asking for a value I do not know how to find. 3 Answers By Expert Tutors Remember that decimal is a positional number system.
Let the digits of the two-digit number be "ab" [this is a*10+b] "reverse the digits in a certain two digit number you decrease its value by 9" means "the sum of it digits is 11" means ---------------- [elimination; add equations] Now, use either equation [eq1] or [eq2] to find the value of b: --------------------------------- [elimination; subtract equations]
Kenneth S. answered • 12/05/17 Expert Help in Algebra/Trig/(Pre)calculus to Guarantee Success in 2018
Suppose the 2-digit number consists of t as the tens position, u as the units position. Then the value of this number is 10t+u. If the digits are reversed, a different number is formed & its value must be 10u+t. Now you have two equations: 10t+u = 10u+t + 9 (because "When you reverse the digits in a certain two digit number you decrease its value by 9"). So you have a system of two equations and two unknowns, which you can solve. |