Respuesta :
Well, you'd start off by combining the two like equations (so 5z + 4z will give you 9z and 8 + 20 will give you 28) so you can have 9z + 28 = 90. You'd subtract 28 from both sides of the equal sign and have 9z = 62. To get z from there you'd divide 62 by 9 and get 6.8888(...) or rounded 6.89
Answer:6.9
Step-by-step explanation: Firstly we start of by opening the bracket to give 5z+8+4z+20=90, then we bring like terms together 5z+4z+8+20=90
to give us 9z+28=90, we bring 28 to the right side 9z=90-28, 9z=62, we then divide both sides by 9 to finally give z=6.88888888,but we round it up to 6.9