Evaluate formulas with "+" symbols For problems that involve using a "1" we must realize there will be two answers; this symbol is asking us to both subtract and add the quantity after the symbol to the value(s) before the symbol. ering When given the formula x [ & I zs we are really being given the two equations x /7 zs and x O z zs . Note we usually write the one with the "-"first, as mathematically that will be the smaller of the two values. Since this type of equation usually yields an interval, the smaller number should come first. Example 1: Given: x X zs , find the two values of x if x [ 150.4, z [ 1.645, s [ 18.2 x x zs, x Ix s x [ 150.4 1.645(18.2), x [ 150.4 0 1.645(18.2) x 150.4 29.939, x 150.4 29.939 x [ 120.461, x 1 180,339 x 120.46, x 180.34 Since there are two values that are called x, depending on the context of the problem we can give them subscripts such as x, [ 120.46, x, 1 180.34 or we can write them mas the interval: (120.46, 180.34) . Note that the smaller of the two values is always written first in the answer. Find the two values of x for x [ * [ is , if x[ 55.32, + 1 2.065, s 1 7.82 When x I & I ts Use x [ [ ts, x [ &0ts The two values are (