7a + 6c + 9a - 15c
-- Look for all the 'a's 7a, 9a
-- Addum up 16a
-- Look for all the 'c's 6c, -15c
-- Addum up -9c
-- Write the results 16a - 9c
6x^2+14x+4
First factor out all numerical factors (=2 in this case)
2(3x^2+7x+2)
look for m,n such that m*n=3*2, m+n=7 => m=6, n=1
2(3x^2+6x + 1x+2)
Factor 3x^2+6x into 3x(x+2)
2( 3x(x+2)+1(x+2) )
factor out common factor (x+2)
2(x+2)(3x+1)
=>
6x^2+14x+4=2(x+2)(3x+1)
Answer:
5 hours
Step-by-step explanation:
if 10 hours cover 650 miles, 1 hour covers 65 miles. When you divide 325 by 65 you get 5 hours.
an easier way is, 650 ÷ 2 = 325 miles, likewise when 10 ÷ 2 = 5 hours
