7x+12 = (x+3 )+ (x+4)

-1

Step-by-step explanation:

7x+12=(x+3)+(x+4)

7x+12=2x+7

5x+12=7

5x=-5

x=-1

step-by-step explanation: given equation a = h(b 1+b 2)

also we are given values of a, h and b 1 as :

a = 16, h = 4, and b 1 = 3.

in order to solve it for b 2, we need to plug the given values of   a, h and b 1 .

therefore, plugging values of   a, h and b 1   in given equation, we get

16 = 4( 3 + b 2)

first dividing both sides by 4, we get

4 = 3 + b 2

subtracting 3 from both sides, we get

4 -3 = 3 -3 + b 2

1 = b 2.

what is the rest of the question? ?