1. factorize m^2-7m-30
Look for two numbers such that their product is -30 and the sum/difference is -7.
1*30 nope
2*15 nope
3*10 yes, 3*(-10)=30, 3-10=-7
So
m^2-7m-30=(m-10)(m+3)
factor the trinomial.
1. m^2-7m-30
2. z^2+65z+1000
3.x^2-45x+450
4.d^2-33d-280
3 answers
thanks , i get it now but can you explain number 2 please
For #2, you need to find two numbers that multiply together to get 1000, and add up to 65. This is easier because it is all positive, so we don't need to worry where the negative sign goes.
1000=1*1000 nope (sum too big)
1000=2*500 nope
1000=4*250 nope
1000=5*200 nope
1000=10*100 nope (sum still too big)
1000=20*50 nope (sum=70, getting close)
1000=25*40 yesss! (sum =65)
Can you take it from here?
1000=1*1000 nope (sum too big)
1000=2*500 nope
1000=4*250 nope
1000=5*200 nope
1000=10*100 nope (sum still too big)
1000=20*50 nope (sum=70, getting close)
1000=25*40 yesss! (sum =65)
Can you take it from here?