Ex 1A:

b)a^2-9a^2+a^2-9a

c)3x^2+5y-3xy+(-5x)

d)x^2-(a+b)x+ab

What is the value of x when x + 7 = 21?

The value of x in this system of equations is 1. 3x + y = 9 y = –4x + 10 substitute the value of y in the first equation: combine like terms: apply the subtraction property of equality: apply the division property of equality: 3x + (–4x + 10) = 9 –x + 10 = 9 –x = –1 x = 1 what is the value of y?

Determine if the solution set for the system of equations shown is the empty set, contains one point or is infinite. x + y = 5 x + y = 7 {} 1 solution infinite