Can someone explain to me what the "subtraction property of equality" is?

i know what the transitive property of equality is: if a = b, and b = c, then a = c.

so for example i have a problem i'm working on where i'm proving vertical angles are congruent. i've already narrowed everything down to transitive property of equality: angle 1 + angle 4 = angle 3 + angle 4. using the subtraction property of equality will be my final step in proving congruency, but i don't know what or how to use this property. ?

Explain step-by-step how to simplify -5(2x – 3y + 6z – 10).

Ten times the square of a non-zero number is eqaul to ninety times the number

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function. a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.