Solve the quadratic by quadratic formula below

a^2-4a=21

a^2 – 4a = 21

by trasponsing 21 to the left:

a^2 – 4a – 21 = 0

by quadratic formula:

x = [- (-4) ± sqrt [(- 4)^2 – 4 (1) (-21)]] / 2 (1)

x = [4 ± sqrt (100)] / 2

x = [4 ± 10] / 2

x = -3, 7

3/4 ÷ 3/4

step-by-step explanation:

basically divide any proper fraction with itself to fit the criteria.

so if we are using 3/4, then:

3/4 ÷ 3/4 = 1

so 1 is the quotient.

and the numerators for both these fractions is 3.   and if we divide the numerators:

3 ÷ 3 = 1

we see that quotient is equal to our original quotient as well.

the solution is the point

step-by-step explanation:

we have

> equation a

> equation b

adds equation a and equation b

substitute the value of x in equation b to find the value of y

the solution is the point