Question

Упростить и найти значения выражений 0.7b+0.3(b-5)= При b = 0.81 (y-7)-(14-y) При y = 0,3 Запись нужна такая. Если b = 0,81, то...

Answer 1

Объяснение:

1)

0,7b + 0,3(b-5)

0,7b + 0,3b -1,5

1b -1,5

1*0,81-1,5=-0,69

2)

(y-7) -(14-y)

y-7+14+y

2y+7

2*0,3+7=0,6+7=7,6

Answer 2

0.7b + 0.3(b-5) =

First, let's simplify the expression inside the parentheses:

0.7b + 0.3(b-5) = 0.7b + 0.3b - 1.5

Now, let's combine like terms:

0.7b + 0.3b - 1.5 = (0.7 + 0.3)b - 1.5 = 1b - 1.5

Next, let's plug in the value of b:

b - 1.5 = 0.81(y-7) - (14-y)

Now, let's simplify the expression on the right side:

b - 1.5 = 0.81y - 5.67 - 14 + y

Combine like terms on the right side:

b - 1.5 = 0.81y + y - 19.67

Now, let's simplify further:

b - 1.5 = 1.81y - 19.67

Now, let's solve for b:

b - 1.5 = 1.81y - 19.67 b = 1.81y - 19.67 + 1.5 b = 1.81y - 18.17

Now, let's find the values of the expressions when b = 0.81:

b = 1.81y - 18.17 0.81 = 1.81y - 18.17 1.81y = 18.17 + 0.81 1.81y = 18.98 y = 18.98 / 1.81 y ≈ 10.49

So, when b = 0.81, y ≈ 10.49.