n2 - 10n + 21 = 0
Two numbers that sum to -10 and multiply to 21 are -3 and -7
So (n - 3)*(n - 7) = 0
Chat with our AI personalities
Multiply the first equation by 3 to give 9x + 15y = 21
8x - 9 = 11x + 12 8x = 11x + 21 -3x = 21 x = -7
x = ab x = 21*37 x = 777
21
15 + 14 + 14 + 11 + 2x + x = 75 Collect like terms 54 + 3x = 75 Subtract 54 3x = 21 Divide by 3 x = 7 ■