Answer:
a=10
Step-by-step explanation:
a^2+b^2=c^2
8 is b
12.8 is c
a^2+64=163.84
a^2=99.84
a=√99.84
a=10
Hope this helps!
Answer:
190
Step-by-step explanation:
10x10x10=1000
then multiply 1000 by 0.19
190
if you meant x^2+9x+20 then it is (x+4)(x+5) you know that because 4+5=9 and 4x5=20 using FOIL
Represent 'a number' by x
7 times x equals 9 more than 4 times x
7 times x=9+4 times x
7x=9+4x
subtract 4x from both sides
3x=9
divide 3
x=3
the number is 3