Simplify 5√7+√7−2√7
a.4√7
b.3√21
c.3√7
d.4√21
i really am stuck on this problem.

7.3

step-by-step explanation:

81+30=111180 minus 111=691/2×19=9.569÷9.5=7.263157895~7.3

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.