Angle a and angle b are supplementary angles. if m angle a = (5x+2) and m angle b = (8x+9) , then find the measure of angle b

You first identify what supplementary angles are,angles that add up to 180.
5x+2+8x+9=180
17x+11=180-11
17x=169
x=169divided by 17
x=9.9411
x=10 when rounded into the next value
8x*10=80+989

Do you have a picture? ?

Look, when you want to do something like put it like x^2. x2 could mean x² or x₂. so to clear confusion, know the notation. to find the product multiply the x's and you get -8x and the y's and you get 6y. since it's all being multiplied it is just -8x6y, or answer a. although the better answer is -48xy(combining -8 and 6) because you should multiply constants whenever you can.