Question

There is a two-digit number whose units digit is six less than the tens digit. Four times the tens digit plus five times the units digit equal 51. Find the digits.

Answer 1

The tens digit number is 9 and the ones digit number is 3.

Answer 2

T = U + 6
4T + 5U = 51 substitute for T
4(U + 6) + 5U = 51
4U + 24 + 5U = 51
9U + 24 = 51
9U = 27
U = 3

t = U + 6
t = 3 + 6
t = 9

Check
4*t + 5*u = ? 51
4*9 + 5*3 = ? 51
36 + 15 =? 51
51 = 51 It checks.