Area and perimeter help me slove

Perimeter:44.91

Area:123.5

Step-by-step explanation:

Perimeter: Starting with the semi circle, the circle has a radius of 5, and pi*radius^2 = 2*pi*radius=pi*5*2=3.14*10 = 31.4

that is the circumference for a whole circle, so the semi circle is 31.4/2=15.7

the perimeter of the triangle is 7+10+ sqrt(7^2+10^2)= sqrt(49+100) = sqrt(149)=12.21

12.21+7+10+15.7=44.91

area: area of the triangle is 7*10=70 70/2 = 45

area of the semicircle is 5 squared * 3.14 which is 25*3.14 which is 78.5

45+78.5= 123.5

a4 - 3a2 - 1

step-by-step explanation:

step   1   :

equation at the end of step   1   :

  ((a4) -   3a2) -   1

step   2   :

trying to factor by splitting the middle term

2.1     factoring   a4-3a2-1  

the first term is,   a4   its coefficient is   1 .

the middle term is,   -3a2   its coefficient is   -3 .

the last term, "the constant", is   -1