Answer:
Step-by-step explanation:
sqrt(28): sqrt(4*7)
sqrt(4) = 2;
sqrt28)=2*sqrt(7)
sqrt(343): sqrt(7 * 7 * 7) = 7 * sqrt(7)
Note: the rule is if you have 3 equal primes under the root sign, you leave one, you throw one away, and you put one outside the root sign.
2 sqrt(63) = 2 sqrt(3*3*7) The above rule gets modified to throw 1 three away and take the other one outside the root sign.
2sqrt(63) = 2*3 sqrt(7)
Numerator: 2*sqrt(7) + 7sqrt(7) = 9sqrt(7)
9sqrt(7)
======
6 sqrt(7)
3/2
Note without brackets I cannot be certain that I have interpreted this correctly. The division only apply to sqrt(343) / 2 sqrt(63). If this is so please leave a note.
Answer:
16 i think
Step-by-step explanation:

Substitute the given value of y into the equation y=7x+15

Move the variable to the left-hand side and change its sign

Collect like terms

Divide both sides of the equation by -5

Substitute the given value of x into the equation y=2x

Solve the equation for y

The possible solution of the system is the ordered pair (x,y)
