Rewrite y = 9x + 7 into standard form. pleas !

Solve this equation using substitution. {4x + y = −2} {4x + 6y = 44}

Jada has a meal in a restaurant she adds up the prices listed on the menu for everything they ordered and gets a subtotal of $42.00. after tax the total is 45.99. what percentage of the subtotal is the total?

I’ve been trying all day to figure this puzzle out. i need the work for it aswell. it is a factoring polynomials tarsia. the image is below.