Please help me I don’t understand

Naomi’s parents want to have 50,000, saved for her college education, if they invest 20000 today and earn 7% interest compound annually, about how long will it take them to save 50 thousand

Solve the equation for x.3(6x - 1) = 12 i've tried doing the math and i can't find out what i'm doing wrong

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.