Suppose you know that MU1() = x1 - 4 and MU2(x) = 2 + 5. Prices are p1 = 1 and p2 = 2. The consumer's income I is unknown. However, you do know that the consumer buys 5 units of good 2, that is you know x2(1, 2, I) = 5 (this means the second dimension of the optimal choice is 5). What is the first dimension x* (1, 2, /), that is, what is the number of units of good 1 that are purchased at the optimal choice