Answer:
since the sum of all angles of a triangle is 180°
Step-by-step explanation:
so 100°+4y+25°+3y+20=180°
145°+7y=180°
7y=180°-145°
7y=35°
y=5°
Answer:
Half-life of the goo is 49.5 minutes

191.7 grams of goo will remain after 32 minutes
Step-by-step explanation:
Let
denotes initial and final mass.

According to exponential decay,

Here, t denotes time and k denotes decay constant.

So, half-life of the goo in minutes is calculated as follows:

Half-life of the goo is 49.5 minutes

So,

Put 

Put t = 32 minutes

Step-by-step explanation:
3x-21+4x²-8x+36
4x²-5×+15