"The sum of -3/8" means -3/8+ some number, which we find out (later in the expression) to be 4×x (that is 4 times x), or 4x. So we add on 4x to the expression, which becomes -3/8+4x. Then, it says "minus 9 times z", so we just take away 9×z. So, the final expression is -3/8+4x-9z.
Hope this helps! I got it right on Edgen.; you should trust me
An algebraic phrase or expression is a mixture of integer constants, variables and algebraic operations like addition, subtraction, multiplication, division and exponentiation. In this problem, you need to isolate first what is grouped together or what needs to be done first which in this sentence, "the sum of negative three-eighths and four. By substitution, it would be (-3/8+4). Then you multiply their sum by x so it would result to (-3/8+4)x. After that it is said that you need to minus that to nine times z which is 9z. This will result to an expression like this (-3/8 +4)x-9z. In the simplest term, the answer would be 9/8x-9z.
