Answer:
4th option
Step-by-step explanation:
x² - 2x - 3 = 0 ( add 3 to both sides )
x² - 2x = 3
using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 1)x + 1 = 3 + 1
(x - 1)² = 4
Answer:
a - a or (a +(-a))
Step-by-step explanation:
A negative plus a positive is always zero if they have the same variable.
So average=(total of scores)/(number of tests)
needs at least average of 70
at least is represented as greater than or equal to or the sign (<u>></u>)
70<u>></u>(total)/(number oftests)
since we have 3 tests, we have to have 3 scores so
70<u>></u>(x+y+z)/3
he scored 85 and 60
70<u>></u>(x+85+60)/3 (doesn't matter which to subsitute)
70<u>></u>(x+145)/3
multiply obht sides by 3
210<u>></u>x+145
subtract 145 from both sides
65<u>></u>x
he needs to get at leas 65 on his third test
